Oil pilferage is one of the most popular and lucrative illegal trade in Assam. But the magnitude of oil theft just outside the Indian Oil Corporation (IOC) terminal in Upper Assam is shocking.

Thatched houses in upper Assam provide the biggest illegal oil storage facility. From the terminals of IOC, fuel is loaded on tankers and sent out to various destinations.

Every vehicle leaving the terminal, parks itself with the rear end towards the thatched house where the oil is collected.  "We just park our vehicles there," said a driver.

Tankers are generally designed with three or four compartments, which contain fuel. It is mandatory for every tanker to contribute at least 20 liters from each of the compartments.

On an average 125 oil tankers leave a terminal daily.

"When the tanker leaves the IOC terminal in Tinsukia and comes to us we are always in doubt about the quality. And of course every single time we receive a tanker it is with a deficit of 50 liters, 100 liters and sometimes 200 liters," said manager, fuel service station.

If the service stations refuse to accept a deficit their next consignment is either cancelled or delayed.

When we approached the IOC, they told us whatever happens outside their premises is not their responsibility.

This is probably the most blatant oil theft of the region. Every single oil tanker coming out of IOC's depot in Tinsukia must offload 60 to 80 liters of petrol or diesel, whatever the tanker is carrying.

The oil tankers then come to service stations, where the owners of the stations are then forced to sign a document, which says they have received a full capacity. The oil that is collected there is adulterated and distributed to several service stations in remote areas.