New Delhi, Dec. 12 -- Work on cleaning and desilting the 1.3km-long Defence Colony drain - a subsidiary channel that ultimately empties into the Barapullah drain - is finally complete after nine months, the Municipal Corporation of Delhi (MCD) and the Delhi Pollution Control Committee (DPCC) have informed the National Green Tribunal (NGT) in separate affidavits.

The drain, covered between 2009 and 2013 as part of a beautification project to create parks on top, had become inaccessible. To clear the massive sediment buildup that had accumulated underneath, engineers relied on what MCD described as a "cut-skip-cut" method: breaking open 19 sections on the concrete cover at intervals of roughly 40 metres.

These openings allowed mechanical ...