# Similarity indexing & GIS analysis of air pollution

## TL;DR

This paper introduces the Delhi Similarity Index (DSI), a new metric for comparing air pollution levels across cities using trace gases, and analyzes GIS data to assess pollution similarities and trends.

## Contribution

The paper formulates the DSI metric and applies GIS analysis to evaluate and compare air pollution levels in Indian cities over several years.

## Key findings

- Bengaluru's pollution levels are approaching Delhi's.
- Jungfraujoch shows moderate similarity to Delhi.
- DSI effectively quantifies pollution similarity.

## Abstract

Pollution has become a major threat in almost all metropolitan cities around the world. Currently, atmospheric scientists are working on various models that could help us understand air pollution. In this paper, we have formulated a new metric tool called Delhi Similarity Index (DSI). The DSI is defined as the geometrical mean of the trace gases such as ozone, sulfur-dioxide and carbon-monoxide, which ranges from 0 (dissimilar to Delhi) to 0.9-1 (similar to Delhi). The limitation of the tool concerning the result of the nitrous-di-oxide data set is also analyzed. Also, the GIS projections of PM 2.5 role for Indian cities are graphically represented. The DSI results from 2011 to 2014 data show that Bengaluru is in the threshold of becoming as polluted like Delhi with values varying from 0.8 to 0.9 (i.e. 80-90%) and Jungfraujoch with a 0.65 to 0.7 (i.e. 65-70%).