Six people, including a police sub-inspector, were killed and 21 others injured when a double-decker AC bus overturned on the Lucknow-Agra Expressway in Uttar Pradesh’s Unnao district early Tuesday, police said.

The accident took place at 5.15 am near Nibha Kheda village when the bus, travelling from Delhi to Bihar with around 50 passengers on board, went out of control and overturned, they said.