The Indian equity benchmarks fell for third day in a row on Thursday amid volatility owing to monthly expiry September futures and option contracts. The benchmarks fluctuated between gains and losses but fell in afternoon trading dragged by selling pressure in banking, information technology and metal stocks. The Sensex fell as much as 394 points to hit an intraday low of 59,019.28 and Nifty 50 index touched an intraday low of 17,590.95.The Sensex ended 287 points lower at 59,126 and Nifty 50 index declined 93 points to close at 17,618.In the September series, Sensex surged 5.68 per cent and Nifty 50 index climbed 5.89 per cent.Ten of 15 sector gauges compiled by the National Stock Exchange ended lower led by the Nifty Bank index’s nearly 1 per cent decline. Nifty Metal, IT, Media, Private Bank, Auto and Financial Services indices also fell between 0.4-1 per cent.On the other hand, Realty, PSU Bank, Pharma, Consumer Durables and Healthcare indexes ended higher.Mid- and small-cap shares outperformed their larger peers as Nifty Midcap 100 index rose 0.42 per cent and Nifty Smallcap 100 index advanced 0.74 per cent.Power Grid was the top Nifty loser, the stock fell 2.82 per cent to close at Rs 189.55. Asian Paints, Shree Cement, Axis Bank, Eicher Motors, Hero MotoCorp, Indian Oil, JSW Steel, HSFL Life, Bajaj Auto and State Bank of India also fell between 1.5-2.2 per cent.On the flipside, Bajaj Finance, Bajaj Finserv, Tata Motors, NTPC, Sun Pharma, Titan, Hindustan Unilever and SBI Life were among the gainers.The overall market breadth was positive as 1,845 shares ended higher while 1,430 closed lower on the BSE.