BENGALURU (Reuters) - Indian shares ended lower for a second straight session on Tuesday, weighed down by losses in financial stocks, while heavyweight oil and gas companies tracked a fall in oil prices. Benchmark indexes NSE Nifty 50 index and the S&P BSE Sensex ended down 0.42% at 15,748.45 and 0.35% lower at 52,549.66, respectively. Markets have struggled for momentum this week following record highs on the back of declining COVID-19 cases, easing of pandemic-induced restrictions and a surge in vaccinations. Sentiment was also dented as global markets inched back from record highs on concerns about new coronavirus outbreaks in Asia undercutting an economic recovery. [MKTS/GLOB] In Mumbai trading, the Nifty Bank Index ended 0.99% lower. Private-sector lenders ICICI Bank and Kotak Mahindra Bank lost 1.6% each. Indian oil and gas heavyweights reflected the dip in oil prices with state-owned companies Oil and Natural Gas Corporation and Indian Oil Corp falling 2.4% each. Worries about slower fuel demand growth due to outbreaks of the highly contagious Delta variant of COVID-19 led to a drop in oil prices for a second day. The Nifty Pharma Index was the only major sector to end in positive territory, gaining 0.58% and posting its third straight session of gains. Drugmaker Cipla added 1.7% after CNBC-TV18 reported the company had received regulatory approval to import the COVID-19 vaccine developed by Moderna. Amongst other stocks, Indian Railway Finance Corp ended up over 2% after reporting a higher profit for the March quarter. Reporting by Shivani Singh in Bengaluru; Editing by Vinay Dwivedi Our Standards: The Thomson Reuters Trust Principles.