The correct answer is (d).
The Bharat Stage (BS) emission norms are emission standards for vehicles in India. They are based on the Euro emission norms, which are developed by the European Commission. The BS norms were introduced in 1991 and have been progressively tightened over time. The latest BS norms, BS VI, came into effect in April 2020.
The BS norms are designed to reduce emissions of pollutants such as carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter from vehicles. These pollutants can cause a variety of health problems, including respiratory problems, heart disease, and cancer.
The BS norms have been successful in reducing emissions from vehicles in India. According to the Ministry of Road Transport and Highways, emissions of carbon monoxide from vehicles have declined by 70% since 1991. Emissions of hydrocarbons and nitrogen oxides have also declined significantly.
The BS norms have had a positive impact on air quality in India. According to the Central Pollution Control Board, air quality in Delhi has improved significantly since 2010. This is due in part to the implementation of the BS norms.
The BS norms are a key part of India’s efforts to improve air quality and protect public health. The government is committed to further tightening the norms in the future.
The US, Japanese, and Global Vehicle Emission Standards of the UN Environment Programme are also important emission standards, but they are not as stringent as the Euro norms. The Euro norms are the most stringent emission standards in the world, and they are used as a benchmark for other emission standards.