A major revision of environmental guidelines in Noida, a suburb of Delhi, means that thousands of flats that are under construction and others that have been built are no longer located in a no-go zone.Environment Minister Prakash Javadekar has signed off on new contours for how much land around the large Okhla Bird Sanctuary should be treated as "eco-sensitive" - it's shrunk from 10 kms to 100 metres on three sides, and a little over a kilometre in the north.60,000 people should be able to collect their apartments within weeks as a result. For years, they have been readied but were declared illegal in 2013 when the National Green Tribunal - the country's environment court - found that the Uttar Pradesh government had not created a large enough buffer zone around the bird sanctuary.Its decision to ban development within a 10-km radius hit major developers including Supertech, Amrapali and Jaypee. Flats in 50 projects could not be delivered to owners because the court barred officials from issuing certificates that declare the buildings are legit.The Environment Minister has sanctioned a proposal suggested last year; the official clearance will be issued next week, Mr Javadekar said.Residential projects in Noida have been running behind schedule by an average of 36 to 48 months because of the delay in resolving the issue. Sales for flats in Noida, a key suburb of Delhi, took a big hit with home-seekers unsure of how safe their investments would remain.