Starting the new fiscal on a positive note, the BSE Sensex today gained 84 points in early trade on increased buying by funds as well as retail investors at prevailing levels.The 30-share index rose by 84 points, or 0.44 per cent, to trade at around 18,920, with sectoral indices led by oil and gas, capital goods and realty, trading in positive zone.The broad-based National Stock Exchange index Nifty rose by over 22 points, or 0.38 per cent, to around 5,705.