LUCKNOW, Dec. 15 -- Dense fog and poor visibility wreaked havoc on Uttar Pradesh streets on Sunday morning, leading to six major road accidents. The mishaps involved at least 22 vehicles and claimed the lives of seven people, including two traders, and injured 10 others, said senior police officials. More than 30 districts, including Lucknow, Jaunpur, Barabanki and Unnao, were under a thick blanket of fog in the morning, when visibility was reported to be at 20 metres or less at several places. In Hamirpur, four people died in a head-on collision between a bus and a car on the Bundelkhand Expressway amid dense fog. Three other car passengers were critically injured. The seven were going to Prayagraj to immerse the ashes of a relative. In Azamgarh, a car spiralled out of control and crashed into a tree in the Jahanaganj police station area, killing two traders from Ghazipur and injuring another. The victims were returning home after buying winter garments from Khalilabad in Sant Kabir Nagar. Police had to cut open the vehicle to retrieve the bodies. In Unnao, a bus rammed into a container from behind on the Lucknow-Agra Expressway in the Behta Mujawar police station area. While the bus driver died on the spot, the conductor and three passengers were injured. More than 20 passengers were on board the bus. In Mathura, four people were injured as four vehicles crashed into each other in a chain reaction. A video of the incident has surfaced, showing a youth trapped in a car being rescued by locals. In Budaun, a loader overturned on the Moradabad Highway due to low visibility. The driver escaped unhurt. In Ghaziabad, a massive pile-up involving 12 vehicles occurred on the Meerut-Delhi Expressway. The accident reportedly began when two cars collided, following which 10 more vehicles rammed them due to poor visibility. Several people sustained minor injuries. Police reached the spot and cleared the traffic....