text: The pharmacies say that online drug retailers are putting customers at risk by failing to follow existing rules.
  The government says it is in the process of drawing up guidelines to regulate online drug sales.
  A number of companies are selling drugs online to tap a market which is estimated to be worth $10bn (Â£65m).
  Although the pharmacies will be shut, customers will be able to buy emergency drugs using special telephone numbers printed on posters and newspapers.
  "It is going to be a 100% strike. Approximately 800,000 chemists will be on strike,"  All India Organisation of Chemists and Druggists chief JS Shinde told AFP news agency.
  "Our own investigation has shown that anti-pregnancy pills, sleeping pills and steroids are being sold freely online."
  Mr Shinde said 40-50% of the business of India's bricks-and-mortar sellers had been affected because of online drug sales.
  "We want the government to close down all illegal online pharma companies immediately."
  India's health ministry said it was drawing up plans 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 on Tuesday.
target: At least 800,000 pharmacies in India are on a one-day strike, demanding an end to online drug sales which they say is affecting their business.