India on Tuesday approved a locally developed, needle-free and nasally administered Covid-19 vaccine for emergency use, in a boost to the country's homegrown pharmaceutical industry.

The new inoculation was developed by Bharat Biotech, which had already developed an intravenous product greenlit by the World Health Organization last November.

India's drug regulator gave the new product emergency authorisation on Tuesday, which will allow it to be used as a primary dose by any unvaccinated or partially vaccinated adult, but not as a booster.

"This step will further strengthen our collective fight against the pandemic," health minister Mansukh Mandaviya said on Twitter.

Bharat Biotech said in a statement last month that it had conducted two successful efficacy trials for the vaccine.

Data from the trials has yet to be given a wider release and it remains unclear when the product will be available for public use.

The announcement comes just two days after China launched the world's first inhalable coronavirus vaccine, Convidecia Air, which is administered through a nebuliser.

India was hit by a devastating spike in Covid cases last year that brought its health care system close to collapse, with oxygen supplies running out and patients scrambling to source medicine from depleted pharmacies.

More than 200,000 people died within a few weeks, according to official figures, though experts believe the real toll is several times higher.

India has since administered more than two billion vaccine doses, fully inoculating more than two-thirds of its 1.4 billion population.