OPEC oil output fell in January, a Reuters survey found on Tuesday, as Iraqi exports declined and Nigerian output did not recover further while Gulf members maintained strong compliance with an OPEC+ deal on production cuts to support the market. The Organization of the Petroleum Exporting Countries (OPEC) pumped 28.87 million barrels per day (bpd), the survey found, down 50,000 bpd from December. In September, OPEC output hit its highest since 2020. The Reuters survey aims to track supply to the market. It is based on shipping data provided by external sources, Refinitiv Eikon flows data, information from companies that track flows, such as Petro-Logistics and Kpler, and information provided by sources at oil companies, OPEC and consultants.