Mumbai, Aug 11 : The key Indian equity indices pared their initial gains on Wednesday morning with the BSE Sensex falling over 200 points. Heavy selling was witnessed in healthcare and auto stocks. Around 10.10 a.m., Sensex was trading at 54,326.44, lower by 228.22 points or 0.42 per cent from its previous close of 54,554.66. It opened at 54,730.65 and has touched an intra-day high of 54,758.74 and a low of 54,303.97 points. The Nifty50 on the National Stock Exchange was trading at 16,211.85, lower by 68.25 points or 0.42 per cent from its previous close. Manish Hathiramani, technical analyst with Deen Dayal Investments said: "The Nifty continues its struggle to keep above the 16,300 level. It is facing resistance every time it tries to conquer it. If we can get past that on a closing basis, we should go up higher to 16,600. On the flip side, a good support lies at 16,100. As long as that holds, we are in bullish terrain." The top gainers on the Sensex were Power Grid, NTPC and Tata Steel, while the major losers were Bajaj Auto, Sun Pharmaceutical Industries and Bajaj Finance. /IANS