State-run power producer NTPC Ltd on Thursday posted a 6.8 per cent decline in net profit at Rs 2,593.4 crore for the quarter ended March 31, impacted by high fuel costs. It had a net profit of Rs 2,781.8 crore in the same quarter of the previous year. The fuel costs grew by 17.7 per cent to Rs 41,635.5 crore, against Rs 35,373.8 crore in the same quarter last year. Meanwhile, a 25-year tax holiday granted to a joint venture of the company with a Sri Lanka government-owned power entity, Ceylon Electricity Board, has come in for intense debate in the Sri Lankan parliament.