An atmospheric phenomenon whereby vehicle exhaust and factory smoke combine with fog.

You are referring to air pollution, also called "smog" (a combination of the words "smoke" and "fog"), a chemical combination of smoke and fog, which is extremely unpleasant and, most importantly, very harmful. In addition to vehicle exhaust and factory smoke, air pollution is also caused by smoke from heaters.

a) it is located in central mexico.

states grant a variety of local governments power to meet residents’ needs (source: apex learning). hope this !