Around 800,000 Indian pharmacies downed their shutters Wednesday to demand a crackdown on online drug sales, which they say is unregulated and eroding their business.

The one-day strike is aimed at curbing India's burgeoning online drug retail industry, which the All India Organisation of Chemists and Druggists (AIOCD) says is putting customers at risk by failing to follow existing rules.

"It is going to be a 100 percent strike. Approximately 800,000 chemists will be on strike," AIOCD president J.S. Shinde told AFP.

"Our own investigation has shown that anti-pregnancy pills, sleeping pills and steroids are being sold freely online."

A slew of companies opened shop online in India last year to tap a market worth more than an estimated $10 billion.

Registered e-pharmacies like 1mg and Zigy say they have teams of pharmacists who vet prescriptions submitted online to counter potential abuse.

But India has no specific rules covering e-retailers, and bricks-and-mortar sellers say drugs are being sold online without proper verification.

"Our business has also been affected by 40-50 percent because of drugs being sold online," Shinde said.

"We want the government to close down all illegal online pharma companies immediately."

India's government said it was in the process of drawing up guidelines to regulate online drug sales.

"A sub-committee has been constituted to look into the matter, which has so far undertaken only preliminary discussions with the stakeholders to ascertain their views," the health ministry said in a statement Tuesday.

Pharmacies will be closed all day, although customers will be able to buy emergency drugs through special telephone numbers printed on posters and newspapers.