Introduction:
Delhi Sultanate was established in 1206 by Qutub-ud-din Aibak and it lasted until 1526. During this time, several cities were developed by the sultans. However, there is one city that was not developed by the Delhi Sultanate.

The cities developed by Delhi Sultanate:
During the Delhi Sultanate period, several cities were developed. Some of the prominent ones are:

- Delhi: Delhi was the capital of the Delhi Sultanate. It was initially developed by Qutub-ud-din Aibak and later expanded by the subsequent sultans. The city was divided into two parts- the old city and the new city.
- Agra: Agra was an important city during the Delhi Sultanate period. It was the capital of the Sultanate for a brief period during the reign of Sikandar Lodi. The city was further developed by the Mughals who made it their capital.
- Jaunpur: Jaunpur was founded by Feroz Shah Tughlaq in 1360. It was an important center of learning and culture during the Sultanate period.
- Tughlaqabad: Tughlaqabad was built by Ghiyas-ud-din Tughlaq in 1321. It was a fortified city and served as the capital of the Tughlaq dynasty for a brief period.

The city that was not developed by Delhi Sultanate:
The city that was not developed by the Delhi Sultanate is Kolkata (formerly known as Calcutta). Kolkata was founded by the British East India Company in the late 17th century. The city was initially a small fishing village named Sutanuti. The British East India Company developed the city as a trading post and named it Calcutta. It later became the capital of British India until 1911 when the capital was shifted to Delhi.

Conclusion:
The Delhi Sultanate period saw the development of several cities. However, Kolkata was not one of them. The city was founded by the British East India Company and developed as a trading post.