(Image source from: www.straitstimes.com)

About 21 people were killed as Polar Vortex continued to freeze the United States Midwest, dipping temperatures to record lows in the region, according to media reports.

The Midwest region comprises Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin.

The Polar Vortex, which is a large area of low pressure and cold air surrounding the Earth's North and South Poles, arrived earlier this week and has for days disrupted life across the entire region, according to The New York Times report.

According to officials, the death victims included a University of Iowa student, a woman found frozen to death inside a Milwaukee apartment after the thermostat malfunctioned and a man died while using a snowblower in Buffalo.

A low of minus 30.5 degrees Celsius was recorded on Wednesday in Chicago, including wind chills, while the city of Rockford in Illinois saw temperatures drop to minus 31 degrees Celsius on Wednesday, the National Weather Service (NWS) said.

Mount Carroll, Illinois, recorded minus 38 degrees Celsius on Thursday. If this confirms, it would become the state's record low, supplanting the previous record of minus 36.

The sustained cold taxed energy systems across the Midwest, leading to some power failures and urgent calls to customers to reduce the heat in their homes. Scores of schools, businesses and eating houses remained closed on Thursday.

By Thursday evening, airlines had canceled more than 2,300 flights in the U.S., according to FlightAware. On Wednesday, cancellations topped 2,700. Throughout the Midwest, hospitals reported patients arriving with symptoms tied to the weather such as frostbite or hypothermia.

-Sowmya Sangam