BEIJING -- China's meteorological authority on Saturday renewed a yellow alert for a cold wave, as most parts of the country will see temperatures plunging over the next few days.

From Saturday to Tuesday, some areas in the central and eastern regions of China, as well as the Qinghai-Tibet Plateau, are expected to experience temperature declines of 6-10 degrees Celsius, the National Meteorological Center (NMC) warned.

The NMC has advised the public to keep warm, while calling for necessary measures to protect crops and aquatic products.

The center also renewed a yellow alert for heavy fog, warning that visibility in some areas including the Bohai Sea, the Yellow Sea and the East China Sea will be reduced to less than 1 kilometer. It added that in some coastal areas of Northeast China and East China, visibility could even be reduced to less than 500 meters.

Drivers have been asked to maintain safe speeds, while airports, freeways and ports have been instructed to implement appropriate safety measures.

China has a four-tier color-coded warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.