Explanation:

- The National Sample Survey Organisation (NSSO) is responsible for conducting large-scale surveys, including those related to poverty estimation in India.

- It collects data on various socio-economic indicators and presents comprehensive reports on living conditions.

- It operates under the Ministry of Statistics and Programme Implementation.

- The Central Statistical Organisation (CSO) is another wing of the Ministry of Statistics and Programme Implementation.

- It compiles statistical data but isn't specifically tasked with poverty surveys.

- The Planning Commission was involved in poverty estimation in India.

- However, it used data collected by NSSO for its reports and policy formulations.

- It has now been replaced by NITI Aayog.

- Niti Ayog came into play after the Planning Commission.

- While it provides policy recommendations, it does not conduct surveys itself.

So, the correct answer is:

Option 1: National Sample Survey Organisation (NSSO)