MUMBAI: India's external debt declined 2.8 per cent to USD 514.4 billion at June-end over the previous quarter on account of a decrease in commercial borrowings, short-term debt and non-resident Indian (NRI) deposits, the RBI said Friday.At end-June 2018, the external debt was placed at USD 514.4 billion, recording a decrease of USD 14.9 billion over its level at end-March 2018.As per the RBI, the decrease in the magnitude of external debt was primarily due to valuation gains resulting from the appreciation of the US dollar against the Indian rupee and major currencies.The external debt to GDP ratio stood at 20.4 per cent at end-June 2018, a shade lower than its level of 20.5 per cent at end-March 2018."Valuation gains due to the appreciation of the US dollar vis-a-vis the Indian rupee and major currencies (viz, Japanese yen, euro, SDR, and pound sterling ) were placed at USD 13 billion."Excluding the valuation effect, the decrease in external debt would have been USD 1.9 billion instead of USD 14.9 billion at end-June 2018 over end-March 2018," RBI said.Commercial borrowings continued to be the largest component of external debt with a share of 37.8 per cent, followed by NRI deposits (24.2 per cent) and short-term trade credit (18.8 per cent).At end-June 2018, long-term debt (with original maturity of above one year) was placed at USD 415.7 billion, recording a decline of USD 11.4 billion over its level at end-March 2018.US dollar denominated debt continued to be the largest component of India's external debt with a share of 50.1 per cent at end-June 2018, followed by the Indian rupee (35.4 per cent), SDR (5.4 per cent), Japanese yen (4.7 per cent) and euro (3.3 per cent), RBI added.