In Punjab, three persons were killed and two sustained injuries in a blast in the boiler of Amonia plant of National Fertilizer Limited at Nangal. <br/> <br/>The explosion occurred due to bursting of a boiler on Saturday. Among the killed two were engineers and a labourer. All the three died on the spot. <br/> <br/>The explosion is suspected to be occurred due to leakage in the Hydrogen gas pipeline. Ropar Dy. Commissioner has ordered a magisterial enquiry in the accident.