> ## Documentation Index > Fetch the complete documentation index at: https://www.worldmonitor.app/docs/llms.txt > Use this file to discover all available pages before exploring further. # China Logistics Corridors > Four reviewed China logistics corridors, six source families, composition rules, provenance, freshness, and API behavior. The China logistics control towers are transparent source compositions over reviewed geographic corridors. They report evidence availability and freshness by family. They do not generate an opaque logistics-risk score, forecast disruption, or infer activity from source presence alone. ## Reviewed corridors | Corridor ID | Name | Reviewed scope | | --------------------------------- | ------------------------- | ---------------------------------------------------------------------------------------- | | `china-yangtze-river-delta` | Yangtze River Delta | Shanghai, Jiangsu, and Zhejiang ports, aviation, and advanced-manufacturing nodes | | `china-greater-bay-area` | Greater Bay Area | Guangdong, Hong Kong, and Macao-facing ports, airports, hazards, and industrial gateways | | `china-bohai-rim` | Bohai Rim | Beijing-Tianjin, Hebei, Shandong, and Liaoning maritime-industrial gateways | | `china-western-land-sea-corridor` | Western Land-Sea Corridor | Inland manufacturing hubs, Xinjiang land crossings, and Guangxi maritime gateways | Each corridor has a reviewed polygon, node registry, node owner, and source selector. A source record contributes only when its selector or reviewed geography maps it to that corridor. National inputs are clearly marked as national and can apply to all four corridors. ## Six signal families | Family ID | Source contract | Scope and observation | | -------------------- | --------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- | | `port` | IMF PortWatch | Reviewed China/Hong Kong port IDs; calls, DWT measures, trend deltas, and anomaly flag when published | | `aviation` | AviationStack | Reviewed PEK, PVG, CAN, SZX, CTU, KMG, URC, and HKG provider coverage | | `hazard` | Western Pacific cyclone sources and Hong Kong Observatory | Events inside a corridor boundary plus explicit HKO warning coverage for the Greater Bay Area | | `power_energy` | WorldMonitor energy spine | National China energy dependency coverage and latest source observation time | | `strategic_industry` | UN Comtrade | Annual strategic-product observations for reporter 156 | | `trade` | UN Comtrade and Shanghai Shipping Exchange CCFI | Annual reporter-156 trade observations and the current China Containerized Freight Index | IMF PortWatch and AviationStack are node-scoped. Hazard observations are regional. WorldMonitor energy spine, UN Comtrade, and Shanghai Shipping Exchange inputs are national. The output keeps those scopes visible rather than presenting national evidence as a measured node value. ## Availability composition Every source signal carries: * publisher identity and class; * source URL when applicable; * node, regional, or national scope; * observation, release, and retrieval time with precision; * revision metadata when available; * transport and content freshness; * an inspectable summary and source metrics. Each family condition is `available`, `partial`, `stale`, or `unavailable`. A corridor is: * `available` only when all six conditions are available; * `stale` when every condition is available or stale and at least one is stale; * `unavailable` when all six are unavailable; or * `partial` for every mixed or provenance-invalid state. An absent configured port or airport becomes an explicit unavailable signal. A healthy feed with zero hazards can establish feed coverage, but it does not create a hazard event. A present energy-spine payload does not establish an activity direction. A current CCFI level without a prior comparison does not become a freight change. ## Freshness budgets The composer evaluates source timestamps at request time: | Input | Transport budget | Content handling | | ----------------------------- | ---------------- | ------------------------------------------------------------- | | PortWatch | 36 hours | Individual observations stale after 72 hours | | AviationStack | 90 minutes | Individual observations stale after 180 minutes | | Western Pacific hazards / HKO | 9 hours | Observations stale after 9 hours | | Energy spine | 48 hours | Year/month/day precision gets a corresponding periodic budget | | UN Comtrade | 48 hours | Annual observations use a 550-day budget | | CCFI | 7 hours | Index content stale after 28 days | Transport freshness proves that collection ran. Content freshness proves that the observation itself is timely. Neither substitutes for the other. ## API and caching `GET /api/supply-chain/v1/get-china-corridor-control-towers` reads the canonical Redis source seeds in one batch and isolates missing dependencies. It validates every composed provenance envelope before returning the wire payload. Healthy aggregates use a five-minute server cache. An all-unavailable result is not positively cached, so a recovery can appear immediately. The client circuit breaker deliberately retains no last-good aggregate that could hide a current fail-closed response. The panel refresh interval is 15 minutes. The response exposes `upstreamUnavailable: true` only when every corridor is unavailable. Partial corridor evidence remains inspectable rather than being collapsed into total outage or false health. This detailed control-tower response is a REST/UI surface. MCP has no dedicated corridor-control-tower tool; Pro MCP receives only its bounded contribution to `get_china_decision_signals`. ## Relationship to the nowcast The [China Activity Nowcast](/docs/methodology/china-activity-nowcast) can use a corridor-family breadth change only when a comparable prior corridor snapshot exists. The control-tower response itself remains a source composition and does not publish a directional economic conclusion.