NEW DELHI, April 11 (Reuters) - India on Sunday (Apr 11) banned the export of antiviral drug Remdesivir and its active pharmaceutical ingredients as demand rocketed due to a record surge in COVID-19 infections and led to crippling shortages in many parts.

Authorities have blamed the ferocious resurgence of the virus mainly on crowding and a reluctance to wear masks.

Still, religious gatherings have continued and Prime Minister Narendra Modi and Home Minister Amit Shah have themselves addressed election campaigns attended by tens of thousands of people, many without masks and hardly any following social distancing.

New COVID-19 cases surged to 152,879 on Sunday, the sixth record rise in seven days, overwhelming hospitals in some regions.

India, known as the pharmacy of the world, has already stalled major exports of coronavirus vaccines.

In addition to the Remdesivir ban "till the situation improves", the health ministry said in a statement that manufacturers had been asked to step up supplies.

Seven Indian companies have licensed the drug from Gilead Sciences, with an installed capacity of about 3.9 million units per month, for local use and exports to more than 100 countries.

The companies are: Cipla Ltd, Dr Reddy's Laboratories Ltd, Hetero Labs Ltd, Jubilant Life Sciences Ltd, Biocon Ltd's Syngene, Zydus Cadila Healthcare Ltd and the Indian unit of Mylan .

The World Health Organization in November issued a conditional recommendation against the use of Remdesivir in hospitalised patients, regardless of disease severity, saying there was no evidence that the drug improved survival and other outcomes in these patients.

Many countries, including India, however, have continued to use it.

India leads the world in the daily average number of new infections reported in more than two weeks, accounting for one in every six infections reported globally each day.

Deaths have also surged, with the health ministry reporting 839 fatalities on Sunday - the highest in over five months - taking the total to 169,275.

India's tally of more than 13.35 million cases is the third-highest globally, behind only the United States and Brazil.

India's new infections have soared nearly 18-fold since hitting a multi-month low in early February.