The country's cut and polished diamond exports in the quarter fell 50% from a year ago to $1.8 billion, the Gems and Jewellery Export Promotion Council (GJEPC) said in a statement.

"Factories were operating with just 10% or 20% workforce because of lockdown. Demand was also weak from overseas during the quarter," Colin Shah, chairman of GJEPC, told Reuters.

Production is still likely to be affected in July and will return to normal levels only after restrictions are eased, Shah said.

India reported a record 28,701 new coronavirus cases on Monday, pushing the country's tally to nearly 900,000 cases, the third highest number in the world, behind only the United States and Brazil in confirmed infections.

Demand has been recovering in China and the United States, two major consumers of gems and jewellery, but is still much lower than normal, Shah said.

The GJEPC estimates that gems and jewellery make up about 15% of India's total exports.

(Reporting by Rajendra Jadhav, editing by Ed Osmond)