No matter how reliable the EIA model is (there are several in the market), bad, insufficient and doctored data can make a travesty of it. To begin with, many kinds of data, such as flora and fauna of a region, have not been updated for decades. Secondly, there is no monitoring of water and air quality in already industrialised regions. In such cases, EIA authors conveniently use data dating back to when there were few or no industries. Then there are some crucial data, such as a river's velocity or volume, which, for reasons of national interest, are kept bottled up as state secrets. But even if the data is outside the purview of the Official Secrets Act, one is often not sure of its authenticity.