GUJRANWALA, Jan 3: Sale of heaters and gas cylinders has picked up in just a couple of days as cold has gripped the city.

A survey conducted by this correspondent on Thursday revealed shops were out of stocks while manufacturers of gas heaters had resorted to black marketing.

A majority of people was using gas heaters in wake of its comparatively cheaper prices. The Sui Northern Gas Pipelines Limited (SNGPL) officials, on the other hand, appealed to the consumers not to use gas heaters for domestic and commercial purpose.

People who afford less used coal and dry wood to save them against cold, it was learnt.