District Supply Officer Ashok Singh told Express Newsline that acting on a tip-off, his team confiscated a tanker with the illegal solvent near Karjan. The tanker was supposed to unload the material at Mehta Chemicals, Thane, but was redirected to Sai Chemicals, Anand, Singh claimed, adding that there was no unit by that name at Anand.

While the district supply officer said the matter was still being investigated, well placed sources said the adulteration of petroleum with solvent was common around the city. Since the density of solvent and petrol was similar, unscrupulous petrol-pump dealers mixed the Rs 8/litre solvent with the Rs 25/litre fuel for increased profits, they said, pointing out that people in the trade were also aware there was no scientific way to detect the adulteration.

According to officials, Sunday's was the third such incident in less than five days. On Tuesday, solvent worth Rs 20,000 was seized from two units in the Waghodia Gujarat Industrial Development Corporation estate.

While District Collector G R Aloria was not available for comment, State Civil Minister Jaspal Singh said there was nothing ``grave'' about the incidents.

According to him, the seizures of fuel adulterants only indicated the "alertness" of the official machinery and not any rise in criminal activity.