Thumba Rocket Launching Station, located in Thiruvananthapuram, Kerala, was India's first rocket launch site. It was established in 1962, and was chosen for several reasons.

1. Geographic location: Thumba is situated close to the equator, which makes it an ideal location for launching rockets. This is because rockets launched closer to the equator can harness the Earth's rotation to gain additional momentum, which can be used to launch heavier payloads or travel greater distances. Additionally, Thumba's location on the coast provides easy access to the sea, which is essential for launching rockets over water.
2. Favorable weather conditions: Thumba experiences favorable weather conditions for rocket launches. The region has a tropical climate with clear skies and low wind speeds for most of the year. This makes it an ideal location for conducting rocket launches without any interference from adverse weather conditions.
3. Proximity to infrastructure: Thumba was selected for its proximity to existing infrastructure such as the Vikram Sarabhai Space Centre (VSSC), which was established in Thiruvananthapuram in 1963. This provided the necessary infrastructure and support for the rocket launch program.
4. Availability of trained personnel: Thumba was chosen because of the availability of trained personnel in the region. The Indian Institute of Technology (IIT) in Madras (now Chennai) was already established in the region, which provided a pool of talented scientists and engineers who could be recruited for the rocket launch program.
5. Security: The remote location of Thumba, combined with the presence of the Indian Air Force (IAF) base in the region, provided the necessary security for the rocket launch program.

In conclusion, the Thumba Rocket Launching Station was chosen for its favorable geographic location, favorable weather conditions, proximity to existing infrastructure, availability of trained personnel, and security. These factors made it an ideal location for India's first rocket launch site, and it continues to play an important role in India's space program today.