I have calculated AQI, WQI, Solid Waste collection efficiency of the concerned city now I want to show all of these in the form of a risk factor or an index
in addition to Michael J. Lynch suggestions you can also look into the environmental performance index (EPI; https://en.wikipedia.org/wiki/Environmental_Performance_Index) to see how they combine the various indices (health impact, air quality, water and sanitation, ...) using weightage factors.
I did not ask you to calculate the EPI using your data. What I meant was to have a look how they do it (and from there come up with your own index). The challenge for you will be to find the suitable weightage factor.
While you are collating the cause/ effects of elements of nature viz. water air land environmnt with flora and fauna,
collect data on Q o L ie Quality of Living in communities.
Can take assessment of Social and Economic wellness with health and what medical interventions that are needed to remedy the ill effects on humans, animals, birds and other living beings.
Bio assets including flora ie trees and plants in all locales.
An audit of bio diversity would reveal all the types, quantity and quality of each assets.
When Audit is duly progressed with Geo spatial details, more clarity is got. And good data is maintained. Can be done on a 3D matrix format for monitoring control and recording.
Well wishes for your great progress for benefit in communities.