India's economy has cause to celebrate. On Nov. 16, Moody's Investment Services upgraded India's sovereign bond rating from its lowest rating to the second lowest. Indian Prime Minister Narendra Modi's chief economic adviser, Arvind Subramanian, took the opportunity to commend the government for its economic reforms. This includes the Goods and Services Tax, implemented July 1 to unify India's states into a single market. The upgraded rating is positive step for the world's fastest growing economy, suggesting an optimistic future for Modi's many reform efforts. But the country's economy still faces challenges....