Wikipedia
XHCDM-TDT
XHCDM-TDT is a digital-only television station licensed to Mexico City, transmitting on channel 21 from Cerro del Chiquihuite. Branded as Capital 21, it is owned by the Government of Mexico City.
It is one of the newest stations in Mexico City; while the government had worked for years to build a station (which, had it signed on in analog, might have been channel 36, 38 or 42), it received its permit on February 22, 2010, and it signed on in 2012.