11.   States have acted jointly before, notably during the Reagan years, to force manufacturers of gasoline-powered vehicles into stricter tailpipe emissions limits than Washington was demanding.

12.   The White House is holding a conference on global warming Monday to drum up public support for some type of emission limits.

13.   As a major coal exporter, Australia has sought exemption from greenhouse gas emission limits, proposing instead differentiated targets that would allow some countries to increase greenhouse emissions.

14.   Attacking one of the major sources of dirty air, the federal standards will require new large trucks and buses to meet stringent tailpipe emission limits.

15.   Australia will not obey any uniform greenhouse gas emission limits if they would impede multi-million dollar energy development deals, the Resources and Energy Minister said Tuesday.

16.   Big industrial nations worry that emissions limits might slow their economies.