More than 200 people took ill after inhaling foul smell and fumes of a hazardous effluent emanating from a nallah near Vadol village in the Ambernath Industrial area in the neighbouring Thane district here on Saturday.

Unconfirmed reports from the affected area said that more than 300 people had complained of uneasiness, suffocation, giddiness, nausea and irritation in the eyes. However, the Thane police late in the evening pegged the number of affected people at 164.

While over 150 affected people were treated and allowed to go home , police said in the evening that only 10 people were undergoing treatment at the hospital. “The condition of all the hospitalised persons is stable,” a senior police official said.

Panic gripped the localities of Ashok Nagar, Sita Nagar, Renuka Society and Ayodhya Nagar and Ramesh Nagar, all located either on the periphery of Ambernath or the nearby Ulhasnagar-3 locality, where people felt  extremely uneasy after inhaling the foul smell and fumes emanating from a nearby nullah. The smell was intense that it spread to nearby areas within a short span of time.

The foul smell was reportedly caused by hazardous effluents discharged into a nullah by a tanker around 3.30 am. There have been several occasions in the past when tankers release effluents in this nullah.

Within next couple of hours, people from the affected areas rushed to the nearby Ulhasnagar Central Hospital where a majority of them were treated and allowed to go. Some affected people also underwent treatment at private hospitals.

As soon as the news of large scale hospitalisation of people spread, a team of Maharashtra Pollution Control Board (MPCB) rushed to the affected area and collected samples of effluents from the nullah. The samples have been sent for chemical analysis.