Vodafone India, India's second biggest telecom operator by subscriber, has challenged the department of telecommunications' (DoT's) decision of not extending its licences for Mumbai, Delhi and Kolkata circles in the Delhi High court.

The telecommunications giant said in a statement that it would take all actions, including legal, required to ensure extension & continuity of its licences in the three circles.

The company stressed that it had the right to extension as NTP 99 as well as licences allocated to it provide for extension & continuity.

In the statement, the company said, "Vodafone filed a petition with Delhi High Court. The Honourable High Court directed DOT to consider the extension applications and give Vodafone an effective hearing."

Vodafone India also claimed that the DoT in February last year had informed the company that the validity of its existing licences might be extended for a period of another ten years.

The telecommunications firm warned that the issues could potentially cause serious inconvenience to millions of mobile users in the Mumbai, Delhi and Kolkata circles. Vodafone India has nearly 155 million subscribers in India.

The licences come up for renewal in November 2014, and as per rules, Vodafone India must apply for renewal of the licenses a year in advance.