NEW DELHI — India’s coronavirus caseload is nearing 850,000 with a record surge of 28,637 in the past 24 hours, prompting authorities to announce a week-long lockdown in the key southern technology hub of Bengaluru. The new confirmed cases took the national total to 849,553. The health ministry on Sunday also reported another 551 deaths for a total of 22,674. India has overtaken Russia in the number of cases and is currently behind the United States and Brazil, according to a tally by Johns Hopkins University. Southern Karnataka state, whose IT hub Bengaluru is home to Microsoft, Apple and Amazon offices, extended Sunday lockdowns to one week beginning Tuesday. New Delhi, Mumbai, Chennai, Bangalore and Pune are among the key Indian cities witnessing a surge in infections. Several states also have announced stringent lockdowns in high-risk areas. Delhi, which has 1,10,921 confirmed cases, on Saturday recorded the lowest number of active cases in the last 31 days, state health department data shows. Not a single coronavirus patient under home isolation in the city has died in July and there has been a "sharp decline" in daily fatality figures in the past two weeks, a government study on COVID-19 deaths has said. The health ministry has advised states and union territories against indiscriminate use of drugs like Remdesivir and Tocilizumab, news agency ANI reported. "The states have been told that the available evidence for Remdesivir suggests that it may decrease the time for clinical improvement when used in moderate to severe cases. However, there have been no benefits in terms of reduced mortality. It has to be used with extreme caution due to its potential for serious adverse effects including liver and kidney injury," a health ministry official was quoted as saying by ANI. — Agencies