At least six people were killed and 25 injured as a powerful bomb went off at the crowded Shringar cinema hall in the industrial town of Ludhiana in Punjab Sunday evening, police said.The blast took place at around 2050 hrs in Shringar theatre located on Samrala road in this industrial town of Punjab.The cinema hall was screening Akshay Kumar starrer "Bhool Bhulaiyya" when the incident happened, DIG (Range) Ishwar Singh said.