"The July–September national accounts validate this weakness."
Gross domestic product growth has dipped to 5.3 percent in the second quarter of 2012 from 6.7 percent a year earlier, with poor output from farm and manufacturing sectors. Growth in private consumption expenditure was one of the lowest in years.
India's exchange rate has fallen over the past year amid interventions by the Reserve Bank of India.
In 2012 India is expected to grow 5.4 percent down from an earlier forecast of 5.6 percent, and a 2013 forecast has been cut to 6.5 percent from 6.7 percent.
"In the Maldives, recent political turmoil, growing concern over the increasing fiscal deficit, rising public debt, and the effect of the weaker European economy on tourism point to continued economic fragility," the report said.
Other economies in South Asia are expected to resilient, ADB said.
Sri Lanka has said it expects growth to be about 6.7 percent this year.China is expected to grow 7.7 percent (8.1 percent next year) and South East Asia 5.3 percent (5.5 percent next year).