The number of mobile phone users in India decreased by 1.82 million in October to 1.14 billion, latest data released by the Telecom Regulatory Authority of India (Trai) showed.
The fall represented the second straight month of decline in subscribers.
Users in the segment had reduced by 3.66 million in September, shrinking for the first time in seven months.
Prior to that, the number of subscribers had last dipped in February, by 3.7 million.
In recent months, it rose by 1.08 million in August, 640,000 in July and 1.89 million in June.
But unlike September, when the fall in users was concentrated in rural areas, the latest monthly dip was seen in urban areas.
The number of users in cities shrank by 1.96 million after increasing by 500,000 in September.
Meanwhile, the number of subscribers in India's vast rural hinterland rose marginally by 140,000, after declining by 3.71 million in September.
Rural subscriptions had seen a see-saw over the past few months, rising by 950,000 in June, falling by 610,000 million in July and rising again in August, by 750,000.
Voda shrinks further
The fall could also be attributed to subscribers leaving Vodafone Idea, which saw its user base shrink by 3.5 million in October, after losing 4 million subscribers in September.
The company has not only been losing subscribers over the past few months, but the pace of loss has accelerated continuously as well.
It lost 1.8 million in June, 1.5 million in July and 1.9 million in August.
Meanwhile, Mukesh Ambani-led Reliance Jio continued to cement its lead in the Indian telecom market as it gained 1.4 million subscribers, up from the 700,000 gain in September.
However, Jio's pace of new customer addition slowed considerably from August when the company had added 3.2 million subscribers.
It had gained 2.94 million, and 400,000 new subscribers in July and June.
Sunil Mittal-led Bharti Airtel added 0.8 million subscribers in October, double that of the 0.4 million additions in September, the data showed. It had added 300,000, 500,000 and 700,000 subscribers in the previous months of August, July and June, respectively,
The government-owned BSNL and MTNL lost 592,404 and 73,395 wireless customers, respectively.
Jio had the highest user base in the country, at 421.3 million as of October 30 followed by Airtel at 365.02 million, and Vodafone with 245.6 million.