According to TERI, Anand Vihar showed higher concentrations than other stations and hinted at a variety of contributing sources.
An analysis carried out by a policy research organisation today said that air pollution levels violated the prescribed limits on the last day of the year and air quality was very "poor" exposing people to high risks of respiratory and cardiovascular problems.
A trend analysis carried out by the The Energy and Resources Institute (TERI) at four locations of the city found concentrations "higher" with respect to the 24-hourly average standards for PM10, PM2.5 and NOx respectively.
"Air pollution levels in different parts of Delhi on December 31, 2015, were more or less similar to the previous day and violated the prescribed limits.
"The averaged concentrations at the four locations (Mandir Marg, RK Puram, Punjabi Bagh and Anand Vihar) were observed to be 4.6, 4.2, and 1.2 times higher with respect to the 24-hourly average standards for PM10, PM2.5 and NOx, respectively.
"This is extremely poor air quality and exposes residents to high risks of respiratory and cardiovascular problems," TERI said in a statement.
The watchdog is carrying out an analysis on three main air pollutants PM10, PM2.5 and NO2 at four locations in Delhi based on the data from government's monitoring network.
"The objective is to analyse the effect of Odd-Even cars scheme on air pollutant concentrations in different parts of the city. This exercise will be done till January 20, 2016 to assess pre- and post- air quality scenarios," TERI said.
It said that Anand Vihar showed higher concentrations than other stations and hinted at a variety of contributing sources.
"Lowest PM2.5/PM10 ratio at Anand Vihar also suggests significant contribution from coarse fraction particulates from crustal, road dust and construction sources to the station.
"PM2.5 concentrations at R K Puram were found to be similar to Anand Vihar, suggesting similar contributions from combustion-based sources - primarily vehicles," it said, adding that other stations although less also showed severe violation of air quality standards for PM and NOx.
TERI has also installed an air quality monitor on the terrace of their office at India Habitat Centre to monitor air quality.