War of the strongest
Planet Earth, Russia.
The climate all over the Earth was many times fiercer compared to the past; warm climates became much hotter and those places where low temperatures prevailed became much more unbearable.
Russia was a country in which cold weather predominated in practically all its territory, and after the evolution of the world, its capital experienced heavy snow blizzards several times a month such that the whole area more than 300 kilometers around Moscow was snow, snow, and more snow.
Due to the invasion of China, the survivors that were located in the south, east, and west of Russia had been moved to the main base located in Moscow, although there were also many other survivors that were abandoned to their fate by the government and the armed/evolved army once they realized that the speed of advance of the Chinese forces was much faster than they had initially expected.