At least seven people were killed and eight injured Saturday when an oil tanker truck overturned and exploded on a highway near Mumbai, news reports said.The tanker slammed into 10 vehicles before it exploded and damaged several shops in Charoti, 100 kilometres north of Mumbai, the IANS news agency reported.Three people travelling in the tanker and four pedestrians were burned alive, local news channels reported, quoting police. The injured were admitted to a nearby hospital where doctors said the condition of five was serious.