A report says that China’s manufacturing activity has fallen to the lowest level in nearly a year as new orders shrank. The preliminary HSBC purchasing managers’ index released Tuesday dropped to 49.2 in March. That’s down from February’s 50.7. The readings are based on a 100-point scale on which numbers above 50 indicate expansion. The report said a “renewed fall in total new business contributed to weaker expansion of output” while companies trimmed staff. The weakness in China’s massive manufacturing sector adds to official worries about the country’s deepening economic slowdown. China’s economy expanded 7.4 percent last year, its slowest pace in nearly a quarter century, and economists predict growth will slow further in the next two years.