At least three people were killed on Monday in a big fire that broke out at a wool factory in industrial hub Ludhiana's Shivpuri area, police said. The victims died due to suffocation, police said, quoting fire department officials. Fire tenders were rushed to the factory to put out the fire. Since the factory had stored a lot of combustible raw material and woollen clothes, controlling the fire was difficult, fire officials said. Ludhiana is located about 120 km from here.