Bharti Airtel shares tumbled as much as 3 per cent to an intraday low of Rs 1,810 per share on the NSE on May 16 amid reports of a block deal. On the NSE, as of 10 AM, Bharti Airtel's counter clocked over Rs 15,000 crore turnover, the highest for any scrip listed on the exchange so far. On the BSE, the turnover crossed Rs 900 crore around the same time.