The correct answer is: Climate vulnerability.
Tamil Nadu is a state in India that is highly vulnerable to climate change. The state is located in a tropical region and is prone to extreme weather events such as cyclones, floods, and droughts. These events can have a devastating impact on the state’s economy and infrastructure.
In addition, climate change is also leading to sea level rise, which is threatening the state’s coastal areas. The state government has taken some steps to address the challenges of climate change, but more needs to be done to protect the state from the impacts of climate change.
The other options are also challenges to planned development in Tamil Nadu, but they are not as significant as climate vulnerability. Urban congestion is a problem in many cities in Tamil Nadu, but it is not as severe as in some other parts of India. Fiscal constraints are also a challenge, but the state government has been able to manage its finances well in recent years. Political instability is not a major problem in Tamil Nadu.
In conclusion, climate vulnerability is the most significant challenge to planned development in Tamil Nadu. The state government needs to take more steps to protect the state from the impacts of climate change.