India's richest state Maharashtra tightened restrictions Friday, citing fears of a "more severe third wave" as the country recorded its third death caused by a new coronavirus variant.

The announcement came days after India's health ministry called Delta Plus a "variant of concern", citing its increased transmissibility and ability to bind to lung cell receptors more easily.

India has recorded 48 cases of the variant so far, with Maharashtra reporting 21 infections -- higher than any other state.

Three people have died after contracting Delta Plus, including one in Maharashtra, the state's health department spokesman Ajay Jadhav told AFP.

Under the new guidelines, malls and theatres in Maharashtra, home to financial hub Mumbai, will remain closed, while restaurants will be permitted to operate on weekdays at 50 percent capacity until 4:00 pm.

Gyms, salons and shops will also have to shut their doors at 4:00 pm, while a limit of 50 guests will be imposed on weddings.

The curbs come less than a month after the state eased restrictions in most districts as coronavirus cases declined following a devastating second wave in the country.

Infections and deaths in India soared to record levels in April and May, overwhelming health services in some places and prompting lockdowns in most of the country.

India has recorded more than 30 million infections since the pandemic began, with Maharashtra accounting for around a fifth of the total cases.