Teams of officials from Excise and police departments carried out searches in the labour camps in Aluva, Angamaly, Perumbavoor and Muvattupuzha and seized banned tobacco products, state Excise Commissioner Rishiraj Singh told reporters.
He said 21 people, most of them migrant workers, were taken into custody in connection with the seizure.
"Around 3,800 to 4,000 kg of banned tobacco products have been seized from these areas," Singh said.
The raid named "Operation Bhai" was held based on complaints from residents of the localities about smuggling of the banned products and also following reported use of ganja and other narcotics by sections of migrant workers, they said.
Singh said a strong anti-drug campaign would be launched in the state from August 1.