Andhra Pradesh Chief Minister Chandrababu Naidu's ambitious plans to build a greenfield capital city for the state at Amravati have again hit a roadblock as the central environment ministry has refused to give clearance for the project.

The state environment authorities have already filed a petition before the National Green Tribunal (NGT) challenging the denial of clearance. However, the Union environment ministry has now asked for "elaborate details" about the huge forest land diversion needed for the project.

The Andhra Pradesh government has asked the Union ministry's approval for diversion of over 19,000 hectares of forest land to build its capital city in Amravati. But, the Forest Advisory Committee has now sought the full details of the project. The Committee is the apex body in the Union environment ministry that is authorised to approve or reject proposals for diversion of forest land.

"The project came to us and we have sent it back as of now seeking all details — exactly how much forest land will be used at what locations and for building what structures. In our view the project proposal sent by the state government is incomplete and we will need more information before considering it as this involves a very large forest area," highly placed officials from the environment ministry confirmed to ET.

The state government officials also confirmed that the ministry has raised questions on the project.

"The state government will comply with whatever the Centre has said. The details sought by the environment ministry are now being collected and we will then send the proposal with all these details to the ministry," said senior AP government officials.

Prime Minister Narendra Modi had laid the foundation stone for the state's new capital Amaravati 22 October. The cost of building the city is pegged at $2 billion (approx. Rs 1.33 lakh crores) and it will be spread across 217 sq km.

Even though the state government is seeking permission for diversion of about 19,000 hectares of forest land, associated infrastructure is expected to affect 50,000 hectares of forest area.

After the environmental clearance from the State Environmental Impact Assessment Authority (SEIAA) for the capital city project in October, Social activist and ex-bureaucrat EAS Sharma has challenged its decision before the NGT disputing that the land being sought for the project falls under "ecologically sensitive area".