LONDON - United Arab Emirates ranked last in an index gauging openness and accountability among nations and organizations that are major donors of global aid, according to a London-based group that said effectiveness of aid is limited when information is not shared.Most major donors worldwide are not open about their activities, according to the transparency index released by the non-profit Publish What You Fund, which campaigns for aid transparency.The Middle East's UAE, which was added to the index for the first time, was followed by the previously bottom-ranking China.The United Nations Development Program (UNDP) topped the index for the second time in a row, followed by the U.S. foreign aid agency Millennium Challenge Corp. and the U.N. Children's Fund (UNICEF).Only a quarter of the 46 donors on the index met standards set out in the International Aid Transparency Initiative (IATI), launched in 2008 to promote the open exchange of information about aid to increase its effectiveness in tackling poverty.Publish What You Fund says developing countries need transparency to manage their resources, and donor countries need to practice transparency to be held accountable."Only 10 out of 46 of the world's largest and most influential donors provided enough information to enable recipient governments to plan, or for citizens to hold their governments to account," said Rupert Simons, its chief executive, in a statement."The 'data revolution' isn't reaching the world's poorest countries," he said.Helen Clark, administrator of the UNDP, said aid transparency is essential to help achieve the Sustainable Development Goals, a blueprint agreed upon by U.N. member states last year to end poverty, hunger and other global woes by 2030."It is encouraging that there has been a marked improvement in aid transparency," Clark said in a statement. "But more needs to be done in order to ensure that development is as effective as possible."