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Environmental Impact Assessment (EIA) is an activity to evaluate the possible impact of an anthropogenic activity on environment. The objective of all development is to add to the economic well-being of the people so that their standard of living can be improved. Development projects are, therefore, taken up to covert the natural resources into goods and services. It is imperative to incorporate environmental aspects into the development projects right at the inception stage to prevent the erosion of the resources base itself. Impact assessment is a handy tool to assess the environmental compatibility of the projects in terms of their location, suitability of technology, efficiency in resource utilization and recycling etc. Impact assessment was introduced in 1978 and now covers almost all major projects.

As present EIA is being done for the following types of projects: (a) (i) river valley, (ii) thermal power, (iii) mining, (iv) industries, (v) atomic power, (vi) rail, road, highways, bridges, (vii) ports and harbours, (viii) airports, (ix) new towns and (x) communication projects; (b) projects which require approval of the Public Investment Board/Planning Commission/Central Electricity Authority; (c) projects referred to the Ministry of Environment and Forest by other ministries; (d) projects which are sensitive and located in environmentally degraded areas; (e) public sector undertakings of the Centre where the project cost is more than Rs.50 crore.

According to a notification issued in January, 1994 EIA is statutory for 29 categories of developmental projects. Under the Forest (Conservation) Act, 1980 diversion of forest land for non-forest purpose requires prior approval from the Central Government. When a project requires both environmental and forest clearance, the proposals are simultaneously processed under the Single Window Clearance Scheme. All cases with complete environmental data and action plans are decided within three months. In the case of diversion of forest land, the decision is taken within six weeks.


Major environmental impacts of river valley projects which need consideration are: (i) degradation of catchment areas; (ii) command area development; (ii) rehabilitation of those affected; (iv) increased incidence of water-borne diseases; (v) reservoir induced seismicity; and (vi) deforestation and loss of flora and fauna including gene-pool reserves.

Ø   Mining Projects

Major environmental impacts of mining operations are: (i) degradation of land; (ii) pollution of surface and ground water resources; (iii) pollution of air; (iv) deforestation including loss of flora and fauna; (v) rehabilitation of affected population including tribals; and (vi) impact on historical monument and religious places.

A major component of the mining operations in India are the open cast mining which severely affects land use pattern. Mining operations have serious adverse impact on the growth of vegetation and general landscape. Minerals extracted interact with surface and ground water thus polluting the water resources. Loss of top-soil due to deforestation also depletes ground water resources and results in drying up of perennial sources like springs and streams especially in hill areas.


The need for wetland protection was given serious consideration at the global level in the early 1960s. A series of conference and meetings held mainly under the auspices of the International Waterfowl and Wetland Research Bureau (IWRB), UK, culminated in the Convention on the Wetlands of International importance, especially as Waterfowl Habitat. Better known as Ramsar Convention and adopted in 1971, it is an inter-government treaty which provides the framework for international cooperation for conservation of wetland habitats. Under the Convention there is a general obligation for the contracting parties to formulate and implement plans to promote the wise use of wetlands in their territories, thereby ensuring the preservation of the ecological character of these habitats. India acceded to the convention in 1982. Six wetlands of India have been designated as Ramsar sites. These are Chilka Lake (Orissa), Keoladeo Ghana National park (Rajasthan), Wullar Lake (Kashmir), Harike Laka (Punjab), Loktak Lake (Manipur) and Sambhar Lake (Rajasthan).

Ø   Thermal Power Projects

Environmental impacts on thermal power projects include: (i) air pollution; (ii) water pollution; (iii) deforestation; (iv) rehabilitation; and (v) land degradation. Fuel gases emerging from stacks containing sulphur dioxide, oxides of nitrogen, carbon monoxide, etc., are detrimental to human beings and vegetation. Water pollution from thermal stations can be due to release of slurry, which is a mixture of flyash and water. Thermal pollution is due to release of cooling waters, which can affect aquatic life. Solution to disposal of ash problem is in its recycling by converting it into building blocks and its use in other construction works. Another step which helps in abating pollution caused by ash in stabilization of ash dumps through suitable vegetation.

Ø   Industrial Projects

Environmental impacts of industrial projects include: (i) air pollution; (ii) water pollution; and (iii) disposal and utilization of solid waste. Impacts of projects in specific areas are examined in great detail and suitable control measures suggested. Concept of recycling, reuse and adoption of clean technologies is increasingly becoming predominant.

Ø   Transport Sector

The environmental parameters affected by the transport projects have been classified into: (i) natural physical resources; (ii) natural ecological resources; (iii) human/economic development resources; and (iv) quality of life values including aesthetic and cultural values. Environmental impacts on above parameters have to be identified and measures should be provided to prevent adverse impacts.

Ø   Coastal Area Management

To protect cultural, aesthetic and ecological values of coastal areas, a notification on Coastal Zone Regulation under the Environment (Protection) Act, 1986 has been issued declaring coastal stretches of seas, bays, estuaries, creaks, rivers and backwaters within 500 metre of High Tide line as Coastal Regulation Zones. Under Coastal Regulation Zones, Setting up of new industries or expansion of existing industries except those directly related to waterfront, manufacturing, handling, storage or disposal of hazardous substances and setting up and expansion of units/mechanisms for disposal of wastes and effluents etc., are prohibited. All seven coastal states are required to prepare coastal management plans which would provide protection to ecologically fragile coastal area rich in biological diversity and provide for land use zoning. Amendment has been made in the Coastal Regulation Zone notification, 1991.

Ø   Nuclear Power Projects

Environmental impacts of nuclear power projects which are of prime concern are: (i) radioactive contamination of air, water and soil; (ii) thermal pollution due to discharge of cooling water; (iii) deforestation and loss of flora and fauna; (iv) rehabilitation; and (v) radioactive waste disposal.


Biosphere reserves are multipurpose protected areas to preserve the genetic diversity in representative ecosystems.

The objectives of biosphere reserves are: (i) to conserve diversity and integrity of plants, animals and micro-organisms; (ii) to promote research on ecological conservation and other environmental aspects; and (iii) to provide facilities for education, awareness and training/fourteen potential sites were identified for setting up biosphere reserve in the country of which eight have been established viz., Nilgiri, Nanda Devi, Nokrek, Great Nicobar, Gulf of Mannar, Manas, Sunderbans, and Similipal, Comprehensive guidelines have been prepared which emphasize on formulation of eco- development and demonstration projects, development of database, conservation plans of key species, establishment of research station New Delhi implementation of social welfare activities. NGOs will be involved in the biosphere reserve programme for creation of public awareness. Latest technologies like remote sensing in studying the reserves will be used.


Wetlands are areas, which are characterized by presence of water and water saturated soil – either permanently, or for a part of the year. India is a signatory of the Ramsar Convention which defines the marshyland. According to it, wetlands are areas of marshes, fens, peatland or water, natural or artificial, permanent, or temporary with water that is static or flowing, fresh, brackish or saline including areas of marine water, the depth of which at low tide does not exceed six metres.

Importance of Wetlands: Wetlands are useful in a number of ways:

  1. i) They are habitat of endangered and rare species of birds, animals, plants and insects.
  2. ii) They sustain migratory birds and waders.

iii)      As an ecosystem they are useful of nutrient recovery and cycling, releasing excess nitrogen, deactivating phosphates, removing toxins, chemicals and heavy metals through absorption by plants and also in the treatment of waste water, (iv) Retention of sediments by wetlands also reduces siltation of rivers.

  1. iv) Wetlands help in mitigating floods, recharging aquifers and reducing surface run-off and consequent erosion.
  2. v) Mangrove wetlands act as buffer against devastating storms.
  3. vi) Wetlands influence the microclimate of the locality in addition to checking of underground salt water intrusion on an adjacent brackish water environment through interface pressure.

Distribution of Wetlands: India has a wealth of wetland eco-systems primarily because of variability in climate conditions and changing topography. They are distributed in different geographical regions ranging from the cold arid zone of Ladakh to wet humid climate of Imphal; warm arid zone of Rajasthan to tropical monsoonic central India, and wet and humid zone of southern peninsula. Most of the wetlands are directly or indirectly linked with major river systems such as Ganga, Brahmaputra, Narmada, Cauvery, Tapti, Godavari, etc.

Conservation of Wetlands: To ensure conservation of wetlands which are important for ecological processes as well as for their rich flora and fauna, an International Convention was held in Ramsar (Iran) in 1971, to provide a framework for international cooperation for the conservation of wetland habitats.

In India national Wetlands Management Committee, which advises the government on policies and measures for conservation and management of the wetlands, has identified 21 wetlands for priority action. These are; Kolleru (AP), Wullar (J&K), Chilka (Orissa), Loktak (Manipur), Bhoj (MP), Sambhar and Pichola (Rajasthan), Ashtamudi and Sasthamkotta (Kerala), Harike and Kanjli (Punjab), Ujni (Maharashtra), Renuka (Himachal Pradesh), Kabar (Bihar), Nalsarovar (Gujarat) and Sukhna (Chandigarh). Nodal research/academic institutions have been identified for each of the selected wetlands.

The action plan for wetlands development include: (i) Survey and Mapping; (ii) Soil conservation measures, (iii) Weed Control, (iv) Control of silt load, (v) Pollution monitoring, (vi) Fisheries Development, (vii) Notification as protected area, and (viii) Environment education and awareness for wetland conservation.


Mangroves are very specialized coastal ecosystems of tropical and subtropical tidal regions of the world bordering the sheltered sea coasts and estuaries. Mangroves vegetation is dominated by salt tolerant inter-tidal halophytic sea plants of diverse structure. They help in the production of detritus and recycling of nutrients thereby enhancing the fertility of the coastal waters to support both pelagic and benthic population of the sea. They prevent soil erosion and act as buffer for the mainland and protect it from the storms. They are also the spawning and nursery grounds for multitude of marine organisms. Mangroves occur all along the Indian coastline in sheltered estuary, tidal creeks, backwaters, salt marshes and mudflats covering a total area of 6,740 sq. km., which is about seven per cent of the world’s total mangrove area.

Mangroves in India have been subject to immense biotic pressure and ruthless exploitation. Schemes for their conservation and management have been initiated by the Ministry of Environment and Forests on the advised of National Committee on Wetlands, Mangroves and Coral reefs. Based on its recommendation 15mangrove areas have been identified for intensive conservation and management purposes. There are: Northern Andaman and Nicobar, Sunderbans (West Bengal), Bhitarkanika (Orissa), Coringa, Godavari Delta and Krishna Estuary (AP), Mahanadi Delta (Orissa), Pichavaram and Point Calimar (TN), Goa, Gulf of Kutch (Gujarat), Coondapur (Karnataka), Achra/Ratnagiri (Maharashtra) and Vembanad (Kerala).


Estuaries, an integral part of the coastal environment, are the outfall regions of the river, making the transitional zone between the fluvial and marine environs. According to Pitchard, “An estuary is a semi-enclosed coastal body of water which has a free connection with the open sea and within which sea water is measurably diluted with fresh water derived from land drainage”. Besides salinity, other parameters that influence the characteristics of an estuary are turbidity, tides, river flow and land drainage.

Estuaries are an important source of natural resources for man and are used for commercial, industrial and recreational purposes. They are the nursery ground for dams and oysters and a variety of shrimps and fishes.

India has 113 major and minor rivers and their combined length is 45,000 Kms. Considerable ecological imbalance has been caused in the estuary ecosystem due to human interference that has finally led to disappearance of their flora and fauna. Release of untreated municipal waste water and industrial effluents into these water bodies lead to serious water pollution including heavy metal pollution, which gets biomagnified and reaches man through food-chain. Overfishing and artificial introduction of species also lead to the imbalance of estuarine ecosystem.

Protection of Estuaries: Following measures should be taken to protect estuaries.

  1. i) The developmental plans for reclaiming land, building barrages or discharging waste should be made with the help of estuarine scientists.
  2. ii) Management of estuaries should be oriented towards the improvement of the estuarine biodiversity.

iii)   Waste-water treatment plants should be set for shore-based industries.

  1. iv) Strict laws should be enacted with regards to dumping of waste into the estuarine areas.
  2. v) Creation of awareness about the importance of estuarine environment among the estuary users.


Lagoons are special type of ecosystems comprising the coastal and open ocean waters having a channel or a series of channels, through which the water is exchanged with the adjacent water body. Lagoons may be of saltish or brackish water. Lagoons are of two types: (i) coastal “lagoon” which is a shallow coastal water body separated from the ocean by a barrier, connected at least intermittently to the ocean by one or more restricted inlets, and usually oriented shore- parallel (Phelger’s definition); and (ii) atoll lagoon is a lake-like stretch of water, enclosed in a coral atoll on coral reef, in the shape of a ring or of a horseshoe.

In India the coastal lagoons are misused by the people as dumping sites for industrial and domestic waste. Human interference in the lagoons for longer periods is due to the slow flushing rate  – and shallowness of lagoons. The impacts of disturbances like sedimentation, pollution ,  eutrophication, erosion and over fishing in the lagoons are difficult to assess. Dredging channels    to accommodate the navigating vessels into the lagoons generate huge quantitative and qualitative changes in the lagoonal flora and fauna. The various industries which are situated near the coastal lagoons release, cold and waste-water into the lagoons which are changing the animal associations in the lagoon systems.

Conserving Lagoons: Lagoons are complex IL systems containing more than one ecosystem; wetlands marshes, sea grass fields, intertidal flats and pelagic system. Hence an integrated approach is necessary for the proper management of lagoons and their resources. Proper planning and the use of scientific technology will help mitigate, or change the ill-effects into beneficial effects. Proper regulatory measures should be adopted and lagoons must be protected against degradation by human activities.


Corals are variety of invertebrate marine organisms that have an internal or external skeleton of stone-like, horny or leathery substance Coral reefs are ridges formed in shallow ocean areas by the calcareous skeletons of which the coral polyps are the most important. Coral reefs are home to a wide variety of flora and fauna.

Corals and coral reefs are facing serious problems due to human pressures including pollutants, siltation from upstream erosion, use of dynamite in mining for construction purposes and poison in fishing. Extraction of corals for the cement industry has been particularly damaging. Scientists have recently indicated that elevated sea temperatures – possible due to global warming -cause coral bleaching, in which the coral’s symbiotic algae, which gives coral its colour, abandon the coral, without these algae, the coral will eventually die. The destruction of coral reefs will destroy an entire system, for several marine organisms are associated with them.

Four coral areas have been identified viz., Gulf of Mannar, Andaman and Nicobar Islands, Lakshadweep Islands and Gulf at Kutchh. The State governments concerned have been asked to draw up management action plans and set up steering committees for appropriate action. A management action plan for the coral reefs of Andaman and Nicobar has been approved.


Under the National Lake Conservation Plan (NLCP) a programme for conservation of selected lakes has been prepared. In the first stage urban lakes, not covered under the existing programmes of the ministry, will be covered.

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