Ahmedabad : Illegal refilling of liquefied petroleum gas (LPG) is turning out to be a highly profitable business in the city. Those involved in illegal trade mint double the profit. This unlawful activity is running without any fear in the city and it becomes hazardous. br br LPG is illegally transferred from a cooking gas cylinder to the other cylinder for domestic and commercial purposes. One normal LPG cylinder can refill eight small cylinders of 2kg or three cylinders of 5kg and a huge profit is made in the process and the authorities are aware of illegal practice but nothing concrete has been done so far, They should keep a tab on illegal activities.