Mumbai: Key Indian equity market indices opened in the green on Thursday following the passage of constitutional amendment bill by Rajya Sabha which paved the way for Goods and Services Tax (GST) Bill, the biggest tax reform of the country. The 30-scrip Sensitive Index (Sensex) was trading 130.82 points or 0.47 per cent higher during the early session. The wider 51-scrip Nifty of the National Stock Exchange (NSE) was also trading 55.10 points or 0.64 per cent higher at 8,599.95 points. The BSE Sensex, which opened at 27,899.88 points, was trading at 27,828.33 points (at 9.15 a.m.) in the early session, higher 130.82 points or 0.47 per cent from the previous day's close at 27,697.51 points. The Sensex touched a high of 27,921.91 points and a low of 27,815.27 points in the trade so far.