In 1990s, Delhi ranked `4^(th)` among the most polluted cities of the world. But now air aqulity of Delhi has significantly improved manily by switching vehicles from diesel to CNG.
a. Expand CNG.
b. CNG is better than diesel .Comment .

Explanation

a.CNG - Compressed Natural Gas .
b. i. CNG burns more efficiently than disel.
ii. CNG is cheaper than diesel.
iii. It cannot be siphoned than diesel.
iv. It cannot be adultered like disel.