LUCKNOW, Dec. 24 -- Dense fog caused a massive multi-vehicle pile-up on a national highway in Amethi district early Tuesday, killing two people and injuring 18 others, senior police officials said. Amethi additional superintendent of police (ASP) Gyanendra Kumar Singh said the accident occurred around 2 am near the Amethi-Sultanpur turn, close to an under-bridge in the Musafirkhana police station area limits, when visibility dropped sharply due to thick fog. He said a truck crashing into a roadside railing triggered a chain of collisions as vehicles following close behind failed to stop in time. At least seven vehicles, including a Uttar Pradesh Roadways bus, three trucks, a car and another heavy vehicle were involved in the crash. Station house officer (SHO) Vivek Singh said, "Two people died on the spot, and 18 others sustained injuries," he said. Rescue teams rushed to the site and shifted the injured to nearby hospitals, where several are stated to be in critical condition. He said relief and rescue operations continued for several hours as police and the district administration worked to clear the highway and restore traffic. Efforts were underway to identify the deceased and injured, he added. In other fog-related accidents on Tuesday, a speeding DCM vehicle rammed a trailer from behind on Ring Road Phase-2 near Lohrapur in Varanasi, leaving the driver seriously injured. In Moradabad, two trucks hit the road divider on the Delhi-Lucknow National Highway near the Katghar police station area due to extremely poor visibility, briefly disrupting traffic. According to the meteorological department, harsh weather conditions are likely to continue on Christmas and the New Year, with dense fog, cold winds and cloudy skies forecast across the state. On Christmas, temperatures are expected to hover between 6degC and 11degC. Meanwhile, the state relief commissioner held a meeting with officials from 25 districts, directing them to remain vigilant. A video advisory has also been issued, urging people to immediately contact emergency numbers '108' and '112' in case of accidents during foggy conditions. To curb accident risks, speed limits on expressways and highways have been capped between 60 kmph and 80 kmph, officials said....