Economist: The most economically efficient way to reduce emissions of air pollutants is to tax them in proportion to the damage they are likely to cause  But in Country Y, many serious pollutants are untaxed and unregulated, and policy makers strongly oppose new taxes
Ttherefore, the best way to achieve a reduction in air pollutant emissions in Country Y would be to institute fixed upper limits on them
Policy makers in Country Y do not oppose setting fixed upper limits on air pollutant emissions as strongly as they oppose new taxes.