* Oct crude steel output at 71.58 mln T vs 73.75 mln T in Sept * Average daily output down 6.1% m/m in Oct * Jan-Oct production down 0.7% y/y (Adds details, background) BEIJING, Nov 15 (Reuters) - China’s daily crude steel output fell 6.1% from a month earlier to 2.3 million tonnes in October, its lowest since December 2017, according to Reuters calculations based on data released by the statistics bureau on Monday. For the month, the world’s top steel producer made 71.58 million tonnes of the metal, falling for a fifth straight month and was down 23.3% from same month a year earlier, data from the National Bureau of Statistics (NBS) showed. China’s monthly steel production has been falling since July after seeing a double-digit growth in the first half of the year. The imposition of strict output controls and curbs on power usage have dented both supply and demand. Weekly capacity utilisation rates at 163 blast furnaces across China plunged to 62.39% as of early November, the lowest since the week ended July 2, data from Mysteel showed, when some heavily polluting industrial activities were halted during the 100th anniversary of the founding of the Communist Party. Downstream demand also failed to meet market expectations especially during the traditional peak construction season in September and October because of the sluggish property market. China’s property investment grew 7.2% in Jan-Oct, having been on a downward trend for eight months. Measured by floor area, new construction starts fell 7.7% year-on-year, the statistics bureau said in a separate statement on Monday. In the first 10 months of the year, China churned out 877.05 million tonnes of steel, down 0.7% on an annual basis, said the NBS. That was the first decline of year-to-date output reported in at least five years and paved way for Beijing to meet its commitment to avoid higher annual output in 2021. Reporting by Min Zhang and Shivani Singh; Editing by Kim Coghill & Simon Cameron-Moore