The deceased has been identified as Satish, they said.
He was hired to fix the fault in plant's refrigeration section. While checking the valve vault of water tank, he fell into it this morning, they said adding that it was yet to be ascertained how he fell into the tank.
An employee of the plant found his body in the water tank.
He was immediately rushed to civil hospital where he was declared brought dead, police said.
The body of deceased was handed over to his family members after the post mortem.