The investigative wing of the Income-Tax department raided the factory premises of 40 textile and paint manufacturers in Surat
Tuesday, an official said.

The raids were conducted by a team of 150 sleuths, with senior officials from the Rajkot Income Tax Commissionerate joining in the raids.

"Incriminating documents" indicating concealed income running up to millions of rupees were reported to have been discovered. The exact amount will be announced after an assessment is made in the next three days, the income-tax department official said.