India’s benchmark index fell to a one-month low, led by utilities and metalmakers, amid concern the Supreme Court decision to cancel coal mining permits and impose a $1.3 billion penalty may raise power generation costs.

Jindal Steel & Power Ltd. fell to the lowest level in 5 1/2 years while aluminum maker Hindalco Industries Ltd. dropped the most in a month. State Bank of India tumbled to a one-month low, sending a measure of lenders to its third day of declines. Jaiprakash Associates Ltd. plunged 20 percent after Reliance Power Ltd. ended talks to buy its hydro assets.

The S&P BSE Sensex lost 1 percent to 26,468.36, the most since Aug. 26. The gauge has slid 2.3 percent this week, poised to halt its longest run of weekly gains in more than two years. The top court Wednesday canceled 98 percent of the coal-mining permits granted in the past two decades and told the government to auction the licenses. Coal generates 60 percent of India’s power and a reliable supply is critical for Prime Minister Narendra Modi’s pledge of unbroken electricity supply by 2022.

The court ruled that mines already in production will be allowed to operate until March 31. It ordered companies to pay 295 rupees a ton on the 273.6 million tons of the fuel mined so far, and a similar amount for the coal they extract through March 31, according to the order. Coal India Ltd. may take over operations from April 1 until the are sold in auction, Attorney General Mukul Rohatgi said yesterday.

The CNX Nifty Index on the National Stock Exchange of India Ltd. fell 1.1 percent to 7,911.85 amid the expiry of monthly derivatives contracts today.

Futures traders rolled over 62 percent of their CNX Nifty contracts as of yesterday, versus a six-month average of 53 percent a day before expiry, data compiled by Bloomberg show.

Foreign investors sold a net $157 million of local shares stocks on Sept. 23, paring this year’s inflows to $14 billion, the most among eight Asian markets tracked by Bloomberg.