They had left the capital on Friday and were slated to reach back home on Saturday.The impact of the collision was such that Ajay 40, Radha 48 and Bharat Thapa died on the spot while the condition of at least four of the injured is critical, police said.There were 19 passengers in the mini-bus, according to officials.The mini-bus plying from Delhi to Nepal had a head-on collision with a petrol tanker in the Kotwali Dehat police station area.