Indian stocks dropped, completing their worst quarter since 2008, as Coal India slid after the cabinet approved a bill making companies mining coal and other minerals pay for development of areas where they operate. Coal India lost 5 per cent, a six-month low. Coal miners must share 26 per cent of their earnings, and other miners must pay an amount equal to the royalty collected by the government for mineral extraction, according to the bill. State Bank of India dropped for a third day, losing 2.1 per cent. The BSE India Sensitive Index, or Sensex, slid 1.5 per cent to 16,453.76 at the 3.30pm close in Mumbai yesterday. The measure lost 13 per cent of its value in the quarter ending, the most since the three months ended December 2008, on concern the Reserve Bank of India\'s record monetary tightening will slow economic growth and erode company earnings. There will be a slowdown and economic growth would be closer to 7.5 per cent, compared with 8.5-to-9 per cent which people were talking about at the beginning of the year,\" K. Ramanathan, chief investment officer with Mumbai-based ING Investment Management, said.