Bolivian regulations have further tightened in recent years and singani is held to significantly stricter standards of chemical purity than what may be allowed in other countries.

The regulations on marine sulfur dioxide emissions are tightening.

The other is more dubious - regulations to tighten accreditation standards and so force colleges to document student achievement.

Under the Date-Rape Drug Prohibition Act of 2000, regulation tightened.

The regulations tighten defector screening processes and slash the amount of money given to each refugee from ₩28,000,000 ($24,180.08) to ₩10,000,000 ($8,635.743).

The regulations, drawn up as part of the Clean Water Action Plan promoted by President Clinton, would tighten supervision considerably.

The new regulations would tighten pollution standards somewhat for cars and mini-vans built in the 2007 model year and afterward.

As regulations like those prohibiting the disposal of liquids in the ground have tightened, Chemical Waste Management's business has grown.

In the decades since, legislation and regulation of vehicular emissions has tightened substantially, and the toxic emissions of cars and light trucks have decreased substantially.

Toyota and Honda have both aggressively pursued more fuel-efficient technologies as regulations tighten around the world.