In which country is ethanol used as a fuel in vehicles?

Domestic sewage contains nutrients like nitrogen and phosphorus which favours the excessive growth of planktonic (free-floating) algae which can accelerate which of the following phenomenon?

Eutrophication is observed in ...... .

Which is the main causative factor of desertification?

$A$ - $BOD$ is a measure of the organic matter present in the water.
$R$ - The lower the $BOD$ of water,the lower is its polluting potential.

Which of the following conferences obtained commitments from different countries for reducing overall greenhouse gas emissions to a level $5\%$ below $1990$ levels by $2008-2012$?