Self-driving cars need high-quality digital maps to function properly. They not only use digital maps to find their general location, but also in some cases to locate landmarks that aid maneuvering in low-viability situations, or when a GPS link isn't available. Consequently, accruing map data has become a major priority for automakers and tech companies. But the world's largest new-car market is throwing up a major roadblock to these efforts.

The Chinese government is blocking foreign companies from mapping its roads in great detail, according to a Financial Times report. The restrictions, which reportedly do not apply to Chinese firms, are being instituted in the name of national security. China is concerned about spying.

China has restricted the recording of geographic information for more than a decade because it believes giving other countries access to that information constitutes a security risk. Geographic surveys can't be performed without permission from the government, and many digital cameras don't record GPS coordinates for geotagging, as they do in other countries, according to Fortune.