(From top) Holes being drilled on an old tyre; the tyre with adhesive tape on it and the tyre at the end of the retreading process

The two most fatal bus accidents this year involved vehicles with retreaded tyres. One of them was last month, when an overcrowded private bus crashed into a branch in Howrah and lost its roof before falling into a trench, killing eight passengers. In the other accident in April, a private bus skidded into Lower Bagjola Canal at Kestopur, killing 21 passengers.

Metro investigates how the illegal business of retreading tyres flourishes in pockets of the city even as they continue to take lives on the road.

What are retreaded tyres?

Tyres have a life span, after which they should be discarded and replaced with new ones. Many owners of commercial vehicles, however, get old tyres retreaded for a few hundred rupees and continue using them.

In retreading units, the worn outer surface of the tyre is shaved off and pores are made on the remaining portion with a special “cutter”. A black adhesive tape is put on the shaved-off surface and a new rubber “sole” is fixed to it. The tyre is then kept in a gas chamber before being fitted to vehicles.

Why is it illegal to use retreaded tyres?

The outer layer of retreaded tyres can come off any time, putting hundreds of lives in danger, said an official of the motor vehicles department.

Who is responsible for preventing the use of retreaded tyres?

The motor vehicles department in Calcutta and the regional transport officers in the districts are responsible for checking the roadworthiness of vehicles, including the condition of tyres. Hardly any steps are taken to stop the use of retreaded tyres.

“It is not possible for our inspectors to check the tyres of each bus on the road. Drivers and conductors of these buses hire new tyres for a few hundred rupees before taking the vehicles for fitness test,” said a motor vehicles inspector.

Where can one get tyres retreaded?

Units that retread hundreds of tyres every month have mushroomed on BT Road, off Rafi Ahmed Kidwai Road and in Topsia. Smith Lane and Blockmann Street, behind Crown cinema, are dotted with such units. Big tyres are retreaded in illegal workshops in Topsia, away from the public eye.

“We only retread tyres of taxis and mini-trucks. Better equipment is needed to retread bus and truck tyres,” said an owner of an illegal unit on Blockmann Street.

There are more than 20 illegal workshops beside the canal in Topsia South. The largest is at 11/1 Topsia South. The workshop has equipment to retread tyres of all shapes and sizes.

“We can retread more than 25 tyres daily. Sometimes, more than 50 tyres are brought in for retreading in a day,” said Kadir, the owner of the workshop.

Police voice: “We will crack down if we have specific information. Retreading is mostly done in motor garages,” said an officer of Topsia police station.