IB Times
A labourer works at a construction site in Kolkata.Reuters file

Poisonous gas from sewers at a leather factory complex in Kolkata killed at least three people and affected other people on Monday. 

The gas leak occurred at the Kolkata Leather Complex, according to the ANI news agency. 

Local news sites reported that the leather disposed in drains had decomposed and formed a toxic gas that killed the three workers who were said to be cleaning the drains. 

At least two other people were admitted to the hospital.