The key Indian equity market indices opened higher on Thursday after the Lok Sabha passed four legislations to introduce Goods and Services Tax (GST) bringing the country closer to a unified tax regime.

The Lok Sabha on Wednesday passed the much-awaited Central Goods and Services Tax (CGST) Bill, Integrated GST Bill, Compensation GST Bill and Union Territory GST Bill 2017, after negating all the amendments put forward by the Opposition.

The Sensitive Index (Sensex) of the BSE, which had closed at 29,531.43 points on Wednesday, opened higher at 29,538.03 points. Minutes into trading, it was quoting at 29,570.48 points, up by 39.05 points, or 0.13 per cent.

At the National Stock Exchange (NSE), the broader 51-scrip Nifty, which had closed at 9,143.80 points, was quoting at 9,147.55 points, up by 3.75 points or 0.04 per cent.

With the March 2017 derivatives contract expiry on Thursday, some caution prevailed in the equity markets.

Indian equity markets extended gains for the second consecutive trade session on Wednesday following positive global cues, a strong rupee and inflow of funds.

The Sensex was up by 121.91 points or 0.41 per cent at the Wednesday's closing. In the day's trade, the barometer 30-scrip sensitive index had touched a high of 29,554.39 points and a low of 29,439.42 points. 

The Nifty too, was up by 43 points or 0.47 per cent.

On Thursday, Asian indices were showing a negative trend. Japan's Nikkei 225 is trading in red, down by 0.34 per cent, Hang Seng down by 0.43 per cent while South Korea's Kospi was down by 0.28 per cent. China's Shanghai Composite index was quoting in red, down by 1.13 per cent.

On a positive note, Nasdaq closed in green, up by 0.38 per cent while FTSE 100 was also up by 0.41 per cent at the closing on Wednesday.