Seven persons were killed and two others seriously injured on Thursdayin during a major fire that engulfed a medical store in Mumbai's Andheri suburb, an official said.The cause of the fire is unclear but it was so intense that it resulted in the deaths in a matter of barely an hour, the official added.While five of them died due to suffocation by the emanating toxic fumes, two sustained severe burns, said the Brihanmumbai Municipal Corporation (BMC) Disaster control.The pharmacy is situated in a chawl on the Juhu gully in Andheri west and went up in flames around 6.15 a.m.The fire was contained within an hour, the official added.