BEIJING, Nov 15 (Reuters) - China’s October new home prices fell 0.2% month-on-month, the biggest decline since February 2015, amid continued demand weakness across the country with authorities holding the line on purchase restrictions to deter speculators. New home prices rose 3.4% year-on-year in October, slower than the growth of 3.8% in September, according to Reuters calculations of data released by the National Bureau of Statistics (NBS) on Monday. Sentiment in China’s property market, which accounts for a quarter of gross domestic product by some metrics, has been rocked by concerns about major property developers grappling with massive debts. (Reporting by Liangping Gao and Ryan Woo; Editing by Christian Schmollinger)