Kolkata, Feb 8 (PTI) West Bengal Chief Minister Mamata Banerjee today wrote a letter to Prime Minister Manmohan Singh requesting him to extend subsidy to fertiliser and waive agricultural loans of farmers in the state. Banerjee told reporters here that she had long been writing such letters to the Prime Minister. ''I wrote to him again today.'' She said such demands had been put forward since the days of the previous Left Front government 'but they could do nothing'. ''So, we want subsidy to be extended to fertiliser and all agricultural loans of the farmers be waived,'' the chief minister said.