Twelve people were arrested in Tiljala, Topsia, Beniapukur and Karaya on Saturday in connection with the manufacture of kite spools with manjha (thread coated with a mixture of glue and glass shards).

Five criminal cases have been drawn up against them, police said.

In the past few months, many two-wheeler riders have been injured and one person was killed on the AJC Bose Road flyover because of kite string injuries.

A two-wheeler rider was injured on Saturday as well on the Parama flyover, the police said.

A raid by officers of various police stations, along with officers of the detective department’s anti-rowdy squad, led to the arrests. At least 53 kites, 76 half-finished spools and 63 ready to use spools were seized. All had manjha rolled over them.

The raids started on Saturday after Sheikh Abdul Salam, 29, a resident of Picnic Garden Road, suffered nose injuries from kite string despite wearing a helmet.

It is difficult to ascertain if any of the injuries or death caused by kite strings can be linked to the kite and spool manufacturers arrested on Saturday, an officer said. “We wanted to send out a message… the manufacture and sale of kites and spools near flyovers will not be allowed.”