High population exodus to the urban centres, inadequate public transport system and poor land-use management are some prevalent problems faced by a developing country. Adulteration of fuel and fuel products, improper traffic management system, poor road conditions, inadequate awareness about the air quality and lack of capital for implementation of programs for air quality improvements are some of the critical issues which are responsible for the deterioration of urban air quality (Central Pollution Control Board, 2010).

National Environmental Engineering Research Institute (NEERI) in its detailed report (2010) states that many places where air quality monitoring was carried out in Mumbai, had very poor air quality. A major contributor of many of the key pollutants such as CO (30-35%), PM (20-30%) NOx (35-70%) was from vehicular traffic. The proportion of their contribution varied according to site conditions and other physical and meteorological factors.

The traffic junctions in India are typically characterized by the existence of buildings with commercial spaces along with complex developments of roadside eateries and retail outlets of others items of daily use. In the vicinity of the road, it leads to high exposure of persons to the pollutants emitted by the vehicles. Further, unauthorized parking of vehicles, improper parking management, slowing of vehicles to find proper parking space, roadside purchases etc., increase congestion at the traffic junctions leading to further increase in emission. Signal system of the junction furthermore complicates the problem of dispersion of vehicular pollution. When vehicles stop at the junction, they keep on idling, but the vehicle-induced turbulence ceases. This leads to trapping of the pollutant inside the street canyon for a longer time and thereby increasing the dosage of people in the vicinity of the junction.

Pollutant Concentration near traffic intersection surrounded by High Rise
Wind Augmentation and purifYing Unit (WAYU): An Induced Air Draft System

To improve the air quality at urban intersections, Wind Augmentation and purifying Unit (WAYU) is developed by Council of Scientific and Industrial Research – National Environmental Engineering Research Institute (CSIR-NEERI) as a part of Technology Development Project being funded by Department of Science and Technology. The device has been indigenously developed can purify the air in an area of the 500-meter square. The device consumes only a half unit of electricity for 10 hours of running and has a maintenance cost of only INR 1500 per month. The device equipped with two ultraviolet lamps and catalyst based system to remove poisonous gases such as volatile organic compounds (VOCs), hydrocarbons (HCs) and carbon monoxide (CO). This device works primarily on two principles:

1. Wind Generation for dilution of Air Pollutants

2. Active Pollutants Removal


The device uses low-speed wind generators, appropriate size filters for long operation cycle with reasonable efficiency along with a thermal oxidizer for removal of carbon monoxide and hydrocarbons including VOCs. The air is passed through the filters and where the particulates are removed. The air generators without a filter can help in augmenting wind turbulence in near zone so that dilution takes place (mimicking nature). In the next level where active pollutants are removed, uses filters and thermal system. The air is heated inside the specially designed with appropriate surface and retention time, within the thermal oxidizers where the carbon monoxide, hydrocarbons, VOCs get converted to carbon dioxide. At the outlet of the device, the air has some residual velocity. This velocity of air creates turbulence in the atmosphere which thereby helps to bring down the pollutant concentrations by the method of dispersion. The device has been tested at a traffic junction, and it is found to reducing the pollutant concentrations by 40-60%.

Latest model of WAYU


Recently, the Union Minister for Science &Technology and Earth Sciences and Environment, Forest and climate change, Dr Harsh Vardhan on September 25, 2018, inaugurated air pollution control device WAYU for traffic junctions at Income Tax Office (ITO) intersection and Mukarba Chowk in Delhi. According to the Union Minister, “ CSIR-NEERI scientists are in the process of developing a bigger version of WAYU which can purify the air in an area of 10000-meter square and also the design of future WAYU devices will have even better aesthetics and can be deployed in bus shelters etc.

WAYU in News/Media

WAYU device to purify air in Delhi: Harsh Vardhan
WAYU : An air pollution control device inaugurated by Dr Harsh Vardhan in Delhi
WAYU: Air pollution control device inaugurated in New Delhi
Dr Harsh Vardhan inaugurates air pollution control device WAYU in Delhi