The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles. The polar vortex contains some of the coldest air on Earth. The air is often contained by a strong jet of west-to-east moving winds that act like a wall, containing the cold air. These winds move at more than 161 kilometres per hour, which help lock the air into the place. 

Further Reading:

• Geography Notes
• Geography Questions and Answers for UPSC