More than 300 people were taken ill with complaints of uneasiness, vomiting, fainting and breathing difficulties after a tanker discharged chemical waste into a drainage system in Thane district near Mumbai on Saturday, said police.

After check-ups, more than 50 people were admitted to hospital. Police have tracked down the details of the tanker which had discharged the effluents and are now trying to locate the tanker's owner.

Police have also taken samples from the drain and are investigating what kind of chemical was discharged into the water.

Industrial incidents take place from time to time in India due to lack of enough security surveillance and facilities to prevent them.