MUMBAI, Jan. 28 -- Seven persons including a two-year-old were injured after a gas cylinder leak triggered a powerful explosion and fire in a chawl in Malwani, in Malad west, early on Tuesday. The explosion took place on the first floor of a chawl near AC Masjid at Malwani Gate No 8. According to residents, LPG leaked from a cylinder during the night and accumulated inside a unit in the chawl. When a family member switched on a light in the morning, a spark from the switchboard ignited the gas, triggering the explosion, they said. Fire officials said the blaze was confined to household articles, edibles, mattresses and other materials. The fire was extinguished at 9:42 am. Neighbours reported hearing a loud explosion that shook the chawl. "We rushed upstairs and saw two injured people coming down the stairs carrying an infant. All of them had burn injuries," said Naushad Khan, a local resident and one of the first responders. Of the seven injured, four were taken to Aadhar Hospital, while three were shifted from Care Hospital to BDBA Hospital. The latter - Vijay Choudhary, 54, Tausib Khan, 18, and Ali Kasim, 17, were treated and discharged against medical advice. At Aadhar Hospital, Julekha Bano Aftaf Ansari, 60, who suffered 55-60% burns, and Adil Shaikh, 2, who sustained 20% burns, were transferred to Cooper Hospital. Roma, 35, and Alisha, 18, both with around 35% burn injuries, were admitted and are said to be in critical condition. Fire officials said the structure suffered significant damage, and the cause of the fire and explosion are under investigation....