Parking in front of shop at main road

Yes. It is illegal to park a car in non-parking areas. If it happens police can take a picture of the same and a penalty may be imposed.
Generally, in cities and towns, we see this problem. Some places will be marked for parking the cars and we should park there only but not wherever we like. In some areas, the police may lift the cars also
and ask the owner to come and meet the police, pay a penalty and then only they can hand over your car to you. As per the new motor vehicle act 2019, the penalties are huge and we should be careful in parking the vehicle.
The following are the parking rules as per the new act.
1. Never park your vehicle in public places where it will become an obstruction to traffic,
2. One should park the vehicle as per the road signs or markings that will indicate the manner in which you have to park the vehicle.
3. One should not park their vehicle in no parking zones.
4. No vehicle should be parked on footpaths and very far away from the foot paths.
5. No parking in private places without permission from the owner of the place.
6. No parking on the wrong side of the road.
7. One should not park the vehicle on the path where there are unbroken white lines.
8. No parking in front of the entrance of any premises.
9. One should not park the vehicle on the bridges.

While parking your car in the public place, you have to ensure whether the area where car is to be parked a prohibited area or otherwise. If it falls a non parking area, you car might be lifted with a crane and finally it is stationed in the police station. The owner of the car is fined heavily for violating the traffic regulations as indicated in the Motor Vehicle Act 2019.
The parking riles under the existing regime is as follows-
1) look out for the safe area which is not objectionable in police angle.
2) Never park your car in the No Parking Zone.
3) No parking to be done in any private area where the owner of the house may raise objections to the police.
4) Ensure that you are not parking your car in an area where it is the entrance zone for any premises.
5) your car stationed in the foot path would attract the police penalty and similarly it should not be parked too far either from the foot path giving a chance of suspicion to the police.
6) Ensure that area where the car is parked is not a bridge causing obstruction to passage of vehicles and public.

There is a parking rule everywhere. You should follow rules and regulations of parking. Do not park your vehicle at a public place where it may cause inconvenience or put other people in danger. You should park your vehicle according to the road signs or markings. You cannot park your vehicle anywhere. Once I parked my car on the main road suddenly one crane came and lifted my car and kept side of the road. Never park your car in the none Parking Zone. Sometimes, police may take the penalty for parking No parking zone.
According to the new motor vehicle act 2019, the penalties are high and be careful in parking the vehicle.

The parking rules differ from place to place. At my place, the main road is having one-way traffic and parking is allowed on the left side only. The parking places are separately earmarked for four-wheelers and two-wheelers. If parking is allowed on the main road and if the place in front of the shop is allowed for four-wheeler parking, then parking your car in front of the shop is not illegal.
A police constable is empowered to take the picture of a vehicle parked in the wrong place or in a wrong manner whether it is a four-wheeler or two-wheeler. A challan may be booked on the vehicle so pictured. Different towns have different parking rules as decided by the traffic police in that area. It is always better to ascertain from the nearest traffic constable whether a vehicle can be parked in that area.

In wide roads in many places in our country police allows parking on one side alternately to ease the traffic. So on even dates one can park in one side and on odd dates one can park in other side. Other than that on all the narrow roads and lanes one cannot park the vehicle in front of the shop or any other establishment as that would choke the traffic. One can only park in the parking slots or some lanes where there is no traffic and police does not mind parking the vehicles there. But on the main roads and busy roads or lanes there is always a danger of towing away of the vehicle by the police. If every shopkeeper parks his vehicle in front of the narrow road then no one can drive through that and it would be a choking of the road or lane which is illegal and is punishable.
The shopkeeper cannot park the vehicle even in the night time giving a plea that in night the traffic is less.
Sometimes police declares or announces a road or lane for one sided traffic (one way) and in that case allows people to park only in one side of the road. These rules are decided by the local police and can change from place to place.