The Subansiri Lower Hydroelectric Project is a controversial project due to:

Potential downstream impacts
Seismic risks
Concerns about ecological damage
All of the above

The correct answer is: d) All of the above.

The Subansiri Lower Hydroelectric Project is a controversial project due to its potential downstream impacts, seismic risks, and concerns about ecological damage.

The project is located on the Subansiri River in Arunachal Pradesh, India. The river is a major tributary of the Brahmaputra River, and the project is expected to have a significant impact on the flow of water downstream. The project is also located in an area that is prone to earthquakes, and there are concerns that the project could trigger landslides or other seismic activity.

The project is also controversial because of its potential impact on the environment. The river is home to a variety of fish and other aquatic life, and the project is expected to disrupt the flow of the river and harm these populations. The project is also located in an area that is home to a number of indigenous communities, and there are concerns that the project could displace these communities and damage their way of life.

The Subansiri Lower Hydroelectric Project has been the subject of protests and legal challenges for many years. The project has been approved by the Indian government, but it is not yet clear when construction will begin.