In India, the first nuclear reactor was established at `…………………..` .

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for the location of the first nuclear reactor established in India.

2. **Recall Relevant Information**: The first nuclear reactor in India is known as "Apsara." It was designed by the Bhabha Atomic Research Centre (BARC).

3. **Consider the Historical Context**: Apsara was built with assistance from the United Kingdom and was inaugurated on January 20, 1957, by the Prime Minister of India.

4. **Conclude the Answer**: Based on the information gathered, the answer to the question is that the first nuclear reactor in India was established at Apsara.

**Final Answer**: Apsara

---