Q. What is the main difference between diesel and petrol car? In same variant 1.6 automatic SX O which is better diesel or petrol - Verna?

First of all both sips different fuel. In Verna, CRDi's ( Diesel) are the newest tech in diesel engines while the naturally aspirated petrols are generation old tech, which are being gradually phased out all over the world. Diesels are more robust engines than petrols & also sips less fuel but mind you diesels do need more maintenance. Diesel cars are more expensive than their petrol counterparts in the same variants. If your daily running is high go for diesel ,if less go for petrol. Before concluding i'd like to point out that Verna is one of the few cars where diesel versions are more powerful than its petrol counterparts pound to pound. Infact the diesel version hilariously decimates the petrol powered Verna.

Petrol cars have more pickup power as compared to diesel cars but diesel cars have more mileage than petrol ones and diesel cars have more maintenance cost as compared to petroltherefore if you need performance go for petrol otherwise diesel