PHOENIX (AP) — A new study says carbon-dioxide pollution has increased dramatically in Arizona over the past two decades.

A report released Thursday by the advocacy group Environment Arizona says the 61 percent rise in CO2 pollution reflects a rapid period of expansion.

It found that the two biggest sources of the pollution caused by the burning of fossil fuels were electric-power generation and automobile exhaust.

The authors argue that the best way to cut pollution levels is to increase the use of renewable-energy sources, such as solar and wind, and more strictly regulate the largest polluters, such as coal-burning power plants.

The group is seeking support for bills in Congress that would cap carbon emissions.