Acting on a tip-off, a police team raided Pallah Morh area where the two tankers bearing same registration number were parked, a police spokesman said.
One of the drivers of the tankers managed to escape whereas the driver of the second truck identified as Harjeet Singh, was arrested, he said.
The sample of the substance present in the tankers was sent to forensic science laboratory (FSL) for testing, he said.
A case under relevant sections have been registered and efforts are on to nab the driver of second tanker, he said.