Two conservancy workers died of asphyxia after they slipped and fell inside a drain at Kalachowkie on Thursday morning.
Pandiyan Durai (25) and Uma Krishnan (26) were cleaning the drain on Ambedkar Road as part of the municipal corporation's pre-monsoon preparation.
Police registered a case of negligence against the contractor, RPS Mehta and Company, and arrested the manager, Ashok Chowdharie, who was present at the site. Police said the firm did not provide the mandatory safety equipment to the workers, which lead to their deaths.
At 9.30 am, Durai first got inside the 30-ft deep drain. "He slipped on the ladder and fell,” said Inspector R Kulkarni. The other workers called out, but when they got no response Krishnan went in. "He too fell to the bottom of the drain," said Kulkarni.
Then Anil Londe (19) went in to look for them. But when he was 8ft inside the drain, he started feeling nauseous and immediately climbed out.
"It was suffocating inside because of the poisonous gases. I am happy to be alive, but am sad I lost my two friends," he said.
Police and fire brigade control room were informed and the workers' bodies got out of the drain. "We will issue a notice to the contractor and consult legal department to take further action against them," said Pravin Shah, deputy chief engineer of the Storm Water Drain department.
"As per the tender conditions, the contractor has to give the labourers all equipment such as oxygen mask, gloves and gum boots," said a civic official, requesting anonymity.
The bodies have been sent to JJ Hospital for post-mortem.