Unauthorized Construction On Public Property

Some people are constructing buildings on government property, which is adjacent to my house. I have met the concerned officers and the local minister but they are not taking any serious action against them. According to the government plan, there should be a road in that space which should continue and get connected to the main road, but because of the carelessness of the development authority no progress is done and it is now a dead end. The culprits are taking advantage of this and constructing the building. I thought of filing a PIL but I am not getting support from my road mates as they have an alternative road. They had constructed a shed before and the government had demolished, this time they are putting mold, it is a re-encroachment. I know we have an alternative road, but what they are doing is illegal, against law. I want to know what will be the question asked by the judge if I put PIL. And I want to what actions to take against them