India, Aug. 1 -- Four people, including three workers, died after allegedly inhaling toxic gases inside an underground water tank at an under-construction building in Assam's Cachar district, police said on Saturday.

The building owner has been detained as police investigate the incident, which occurred on Friday, 31 July, in the Kumarpara area of Jaynagar.

According to police, one worker entered the tank to clean it but did not return. Two other workers climbed down to check on him, while a local resident entered the tank in an attempt to rescue them. All four lost consciousness inside.

Residents pulled them out and rushed them to Silchar Medical College and Hospital, where doctors declared them dead.

The victims were identified as N...