Foreign charities and non-profit groups operating in China prepared for the introduction of a new law that will curb their autonomy and allow local authorities to closely regulate their activity. A Human Rights Watch report raised questions over the legality of methods used by authorities in their war against corruption. Air pollution wreaked havoc in northern China as tens of thousands of people fled dangerous smog and around half a billion people were forced to live under toxic conditions. A car bomb detonated in southern Xinjiang, killing one person and injuring three. The Chinese Navy seized a United States (US) underwater drone in the South China Sea. Satellite imagery revealed that Vietnam commenced dredging on the Ladd Reef, a disputed island in the Spratly chain. As tensions in the region continue to heighten, both Japan and China opted to increase their defence budgets. Construction of the Chinese-Laos railway line began on 25 December in the northern Lao city of Luang Prabang.