India's BSE Sensex closed about 0.5% up at 81,644.4 on Tuesday, its highest since July 24, notching its fourth straight session of gains, led by autos. Market sentiment was buoyed by continued optimism surrounding PM Modi’s GST reforms and signs of easing geopolitical tensions between Russia and Ukraine. Among Sensex firms, Tata Motors rose the most by 3.6% while Adani Ports added 3.2%. Heavyweight Reliance Industries rose by 2.8% spurred by news that Reliance Consumer Products, a unit of the conglomerate, had acquired a majority stake in a joint venture with Naturedge Beverages. The deal enables Reliance to enter the rapidly expanding healthy functional beverages market. Eternal, Tech Mahindra, Kotak Mahindra Bank, Hindustan Unilever and Maruti were also among the gainers. However, Bajaj Finserv, Power Grid, Mahindra & Mahindra, BEL and HCL Tech posted the biggest declines, ranging between 0.5% and 1%.