Bharat Stage VI emission norms were implemented in India in two stages: Stage I from April 1, 2020, and Stage II from April 1, 2023. For M & N category vehicles, the RDE test along with other applicable certification tests is mandatory for obtaining a BSVI compliance certificate during stages I and II. The RDE test is conducted on roads under real driving conditions, unlike the Type-I test, which uses a predefined cycle on the chassis dynamometer, during which the ambient temperature and other environmental conditions are controlled in a narrow range. During BSVI Stage I for the RDE test, there was no limit for any pollutant. Therefore, it is considered as the RDE monitoring stage, and from BS-VI Stage II, limits are enforced on a few pollutants (NOX and PN) as notified in notification GSR 226(E) dated March 27, 2023. Therefore, it is considered the RDE compliance stage. During the RDE monitoring phase, emissions from M & N category vehicles are comparatively higher because of several reasons such as cost reduction, weight reduction, and optimization of exhaust after treatment systems to meet only the Type-I limit, irrespective of those vehicles’ emissions during real driving conditions. However, to meet the RDE limits in the compliance stage, exhaust aftertreatment components such as the gasoline particle filter (GPF), selective catalyst reduction (SCR), and some other sensors and components are added to both categories of vehicles, along with calibration optimization. This study was conducted on all the characteristic vehicles, such as vehicle category, ignition type, engine capacity, etc., to obtain an overview of the advancement in exhaust aftertreatment components and their RDE emission performance from the RDE monitoring stage to the RDE compliance stage.