Google Inc reported an unusual drop in traffic to its sites in China, and an Internet monitor said the search engine’s services are being blocked in the world’s most populous nation. Google’s Transparency Report, which measures traffic to its sites around the world, showed a bigger-than-typical plunge in China traffic yesterday. The company’s services, including mail, maps and document storage, are being blocked in China, according to Greatfire.org, a website that monitors Internet activity and access in China.