The researchers analyzed the ecological footprint of Huhhot, Baotou, and Erdos in Inner Mongolia from 1990 to 2010. They found that Erdos had the highest ecological footprint, Baotou had the second highest, and Hohhot had the lowest. Hohhot's ecological carrying capacity decreased over 21 years, while Baotou and Erdos increased. Hohhot had an ecological surplus that decreased over time, while Baotou and Erdos shifted to an ecological deficit. The ecological pressure index and ecological risk degree increased in recent years, with Hohhot at an intermediate ecological risk level and Baotou and Erdos at an advanced level.