Durgapur, Dec. 18: The CPM’s labour arm has stopped work in an RPG Group-owned Asansol mine that supplies coal to CESC’s power plants, demanding “recognition letters” to all contract workers.

When it struck work on Monday, Citu had also demanded payment of dues to drivers and helpers who had been declared surplus. The contractor accepted the demand, but the letter remained a sore point.

CESC officials said its plants at Budge Budge, Titagarh and Garden Reach had about a fortnight’s stocks and power supply to Calcutta would not be affected immediately.

Citu leader Uttam Chakraborty said there was no way it could back off. “If the contractor is replaced tomorrow, what will happen to the workers?”