NY -- Standard & Poor's CreditWire 5/22/98 -- Standard & Poor's today affirmed the Republic of India's long-term foreign currency issuer credit rating of double-'B'-plus and its local currency issuer credit rating of triple-'B'-plus. At the same time, Standard & Poor's changed the outlook on both ratings to negative from stable. The change in the outlook reflects the erosion of India's external financial position following the imposition of sanctions by the U.S. and other countries in response to nuclear tests carried out by India last week. While the country's ample foreign currency reserves û about $25 billion, or twice its stock of estimated short-term debt û should allow it to absorb the near-term impact of sanctions, India's balance of payments