The document discusses carbon tax, which is a tax placed on carbon dioxide emissions from the use of fossil fuels. It aims to reduce CO2 emissions and protect the environment by making carbon-intensive activities more expensive. While a carbon tax has advantages like economic growth and emission reductions, there are also disadvantages like increased costs for companies and the poor. Only a few countries have implemented carbon taxes successfully so far. The document concludes that a carbon tax is important for environmental sustainability but will be challenging to implement in India due to economic priorities.