Corporation sources said a private hospital was fined Rs 10 lakh for illegally dumping medical waste into a nearby canal.
They said Corporation Commissioner R Sateesh led a team in carrying out a surprise inspection at the hospital in Asthampatty and found venomous snakes in the tanks that supply drinking water.
The officials noticed Aedes mosquitoes, which spread dengue, in plastic material and medical waste and also in the water tank there, they said.
A fine of Rs five lakh each was imposed on two spinning mills at Thathampatty and Kamarajar colony, where mosquito larvae were found in drums, oil cans and other materials, while a tea shop owner was fined Rs 25,000 as larvae were found in the water tank kept there.
On October 15, the Tamil Nadu government had apprised Union minister Ashwini Kumar Choubey of the steps being taken to combat dengue in the state and also took up its demand for a central-aid of Rs 256 crore to tackle the situation.