In the early expansion of the Indian mobile market, which telecom company became the first to achieve a 15 million subscriber base?

Introduction / Context:
Telecom growth is an important part of business awareness because it reflects how infrastructure and consumer markets evolve in a country. This question focuses on a milestone in India, asking which company was the first to cross a subscriber base of 15 million, a major achievement during the early phases of mobile penetration.

Given Data / Assumptions:
- We are looking at the first telecom company to reach 15 million subscribers in India.- The options are well known operators from the early mobile era: BSNL, Airtel, Reliance and Hutch.- The timeframe is during the rapid growth of mobile connections, before subscriber numbers crossed hundreds of millions.- Only one company achieved this landmark first.

Concept / Approach:
Bharat Sanchar Nigam Limited (BSNL) is a government owned operator. Airtel, Reliance and Hutch (now part of Vodafone Idea) are private players. Among them, Bharti Airtel is widely recognised as an early market leader in India's mobile segment. It was frequently highlighted in the media for crossing major subscriber milestones ahead of competitors. Therefore, identifying the most aggressive early private player helps in deducing the correct answer.

Step-by-Step Solution:
Step 1: Recall which operator consistently led subscriber numbers in business news during the initial years of Indian mobile growth.Step 2: Note that Bharti Airtel was often described as the largest cellular service provider in India, announcing milestone achievements like being first to cross 10 million and then 15 million customers.Step 3: Compare this to BSNL, which grew strongly but entered cellular services later in many circles.Step 4: Recognise that Reliance and Hutch also grew, but media reports identified Airtel as the first to reach 15 million users across its network.Step 5: Choose the operator most consistently associated with such early milestones, which is Airtel.

Verification / Alternative check:
An alternative way to confirm is to think of brand positioning. Airtel marketed itself as the largest mobile network in India and frequently used subscriber figures in its branding. Business articles and telecom reports from that period highlight Airtel as the first private operator to cross specific subscriber benchmarks nationwide. If you cross recall this with the timeline when BSNL and Reliance were still expanding their networks, it further supports Airtel being the earliest to the 15 million mark.

Why Other Options Are Wrong:
BSNL: Although it had a large landline base and later many mobile customers, it was not the first to cross the 15 million mobile subscriber milestone nationwide.Reliance: Entered mobile services aggressively but reached major subscriber milestones after Airtel in the national ranking.Hutch: Successful in several circles but smaller in overall national scale compared to Airtel at that time.

Common Pitfalls:
Many learners guess based on who they personally used as a provider rather than focusing on national data. Another mistake is assuming that BSNL must have had the largest base because it is a public sector company, which ignores the rapid expansion by private players. To handle such questions, connect the milestone with the operator most frequently described as market leader in early telecom reports, which in this case is Airtel.

Final Answer:
The first telecom company in India to achieve a 15 million mobile subscriber base was Airtel.