NEPBIOS/ASPT

Class

Description

Color Code

7.00 - 10.00

I

Non to very slight pollution

Blue

5.50 - 6.99

II

moderate pollution

Green

4.00 - 5.49

III

Critical pollution

Yellow

2.50 - 3.99

IV

Heavy pollution

Orange

1.00 - 2.49

V

Very heavy to extreme pollution

Red