This document summarizes the evolution of emission standards in India for vehicles. It discusses the introduction of Bharat Stage standards beginning in 2000 based on European regulations. BS III standards were implemented nationwide in 2010, while BS IV was introduced in 13 major cities in 2010 and nationwide in 2017. The Indian government decided to skip BS V and adopt the more stringent BS VI standards by 2020 to address air pollution issues. The document also provides an overview of emission standards introduced in India from 1991-2020, becoming progressively more strict over time.