The handbook of Environmental Impact Assessment prepared by the Ministry of Environment and Forests, Government of India categorizes all infrastructure projects (including construction and expansion of rail, road, waterways and airports) in the transportation sector under the Schedule - I projects. As per the EIA notification (Anon., 1994a) for all such projects, EIA studies are mandatory requirements for obtaining environmental clearance for the implementation of such projects.

The proposal for the construction of an Airport at Lengpui in Mizoram was moved by the Government of Mizoram in the year 1995 for consideration by the Ministry of Environment and Forests along with the report on the EIA studies conducted by M/s Engineers and Management Associates, New Delhi.

The project was considered for environmental clearance in the meeting of the Expert Committee for infrastructure and miscellaneous projects in December 1996. Information on the existence of endangered species of flora and fauna in the site proposed for airport and an assessment of the possible adverse impacts of the incremental traffic on the wildlife habitat was a specific requirement of the Expert Committee prior to the consideration of the project for the accordance of environmental clearance. A request to the Wildlife Institute was made by MoE&F vide letter no. J.16011/43-95-IA-III dated 18.12.96 to provide the above information. This was also followed by the request from the Resident Commissioner, Government of Mizoram vide the letter No. F23015/8/95-RC dated 30.12.95 to undertake studies to furnish the information desired by MoE&F. In response to these requests, the Wildlife Institute of India took upon it the task of ecological assessment under the consultancy offer of Government of Mizoram.