LUCKNOW, Dec. 14 -- Dense fog led to a series of road accidents and multi-vehicle pile-ups across Uttar Pradesh, claiming four lives and leaving at least 22 injured, confirmed senior police and administrative officials on Saturday. Visibility in many areas dropped to as low as 10 metres, making driving extremely hazardous. According to officials, at least eight major road accidents were reported from different parts of the state due to poor visibility, involving around 38 vehicles. For these accidents, the officials blamed thick fog in at least 30 districts, including Lucknow, Unnao, Barabanki, Sultanpur, Raebareli, Amroha, Bulandshahr, Bareilly, Mau and Gorakhpur. The Meteorological Department has issued a dense fog alert for the next two to three days for the northern districts of Purvanchal and the Terai regions of western Uttar Pradesh, urging motorists to drive cautiously and avoid unnecessary travel during early morning hours. In Unnao, a speeding truck collided with an auto-rickshaw. Three occupants of the auto-rickshaw died on the spot. Their bodies were reportedly thrown several metres away due to the impact. Amroha also witnessed a deadly crash involving four vehicles, including a tractor-trolley, a bus and two cars, in which one person was killed. In Sultanpur, an SUV rammed into a stationary car on the Purvanchal Expressway amid dense fog. Moments later, a truck hit the SUV from behind, causing a serious head injury to a woman. I n Rae Bareli, a truck broke through the railing of a bridge and was left dangling, though the driver managed to jump out and escape unhurt. In a pile-up on the eastern peripheral expressway in Noida, 15 vehicles rammed into one another. The chain collision was triggered by an initial crash between a truck and a car. Six people suffered minor injuries in the incident. In Bulandshahr, eight vehicles collided on a highway, leaving 10 passengers injured. Fog-related accidents were also reported from Pratapgarh, where a school bus heading to pick up children collided head-on with a car. Although two to three children were on board, no injuries were reported. In Mau, three vehicles collided due to low visibility, seriously injuring five people....