Millions of people are celebrating Lunar New Year, also known as Chinese New Year, the most important annual holiday in much of Asia, BBC reports. The New Year began in China at midnight, with firework displays and family gatherings. It marked the opening of the year of the snake, taking over from the dragon. In China, an estimated 200 million people have travelled to be with their families in what is considered the biggest mass human migration on Earth. The holiday will continue throughout the week, with government offices and businesses shut down. The snake has a mixed reputation in China. It is associated with wisdom, beauty and intelligence but also pride and anger. Residents of Beijing braved freezing temperatures on Saturday night to let off fireworks, which are believed to ward off evil spirits. However, the displays in the capital were reportedly more muted than in previous years, starting later at night than usual and ending earlier on Sunday morning. The city authorities had asked people to set off fewer fireworks because of dangerous levels of air pollution and a high number of smoggy days during the past month.