New Delhi, March 11 -- If gross domestic product (GDP) growth, manufacturing activity, contained inflation and comfortable import cover are India's muscle, the rupee and stock markets are proving to be its Achilles' heel.

These external vulnerabilities have repeatedly prevented the country from claiming the top position on Mint's Emerging Markets Tracker more consistently. As India grapples with these weaknesses, Vietnam-newly added to the tracker-has emerged as a formidable challenger.

Vietnam has claimed the top spot in three of the past four months, marking a strong debut on the tracker. However, over a longer horizon India retains a narrow lead. Over the past 12 months, India ranked first six times compared with Vietnam's five.

The...