A police case or FIR has been filed suspecting sabotage behind the fire. "Prima facie it looks like an act of sabotage and the municipal corporation has filed a case with the police against unknown person," Municipal Commissioner Ajoy Mehta said.

12 CCTV cameras have been installed at the dumpyard; 20 more will be installed later.

About 95 per cent of the fire was brought under control by the afternoon after 12 fire engines battled the blaze. But toxic smoke continues to engulf the area, with residents complaining of discomfort and breathing problems.

"Our children can't breathe. My son's respiratory problems have worsened in the last two months," a resident of the area told NDTV. "Smoke enters our houses. It gets extremely difficult to breathe or eat. Promises are made when ministers visit, but then no action is taken," added another.

The fire intensified on Sunday evening and spread to two-three square kilometers. Smoke was visible from as far as Vashi bridge till the end of the Ghatkopar-Man-Khurd link road.

A massive fire had broken out at the dumping yard, spread across 326 acres, on January 27. It was brought under control after seven days of round-the-clock fire-fighting.

Government schools in central Mumbai's Shivaji Nagar and Deonar were forced to remain closed for two days due to thick smog caused by the fire.

Experts blamed the lack of waste management policy and crammed dumping yards in Mumbai's municipalities for the Deonar fire.

Union Environment Minister Prakash Javadekar today promised stern action. "We are sending special teams to the site. They will give a full report within a week. Whoever is responsible will not be spared."