Indraprastha Gas Ltd reported a 17 per cent increase in net profit for the fourth quarter ended March 31 on increased sale volumes..The net profit in the January-March quarter rose by 16.78 per cent to Rs 80.75 crore compared to Rs 69.15 crore in the same period a year ago, IGL said in a statement..IGL, the sole supplier of CNG to automobiles and piped cooking gas to households in national capital region, said sales volume growth was 18 per cent in the fourth quarter. CNG sales volume grew by 15 per cent, while piped gas sales recorded a 33 per cent growth.."During this period, IGL registered a turnover of Rs 798 crore as compared to Rs 566 crore in the corresponding period last year thereby registering a sales value growth of 41 per cent in financial terms," it said.