<P> It has been said that `` Mexico City 's air has gone from among the world 's cleanest to among the dirtiest in the span of a generation . '' Historic air pollution episodes of the 1950s led to acute increases in infant mortality . </P>
<P> It has been said that `` Mexico City 's air has gone from among the world 's cleanest to among the dirtiest in the span of a generation . '' Historic air pollution episodes of the 1950s led to acute increases in infant mortality . </P>
when did air pollution start in mexico city
when did air pollution start in mexico city
1950s
1950s