Question: What is the busiest airport in the region including  Central Maryland and Northern Virginia?
Context: Chennai International Airport (IATA: MAA, ICAO: VOMM) is an international airport serving the city of Chennai (Madras), Tamil Nadu, India and its metropolitan area.  It is the fourth busiest airport in India in terms of total passenger traffic after airports at Delhi, Mumbai and Bengaluru.  It is the 49th busiest airport in Asia for CY 2016.  In the fiscal year 2016-17, the airport handled over 18.3 million passengers.  Over 400 aircraft movements are handled by the airport per day.  Third busiest Airport in terms of cargo handling in India.  The planned extension of the terminals are about to start as the union government has told that Chennai might not get its new airport soon. Dubai International Airport (IATA: DXB, ICAO: OMDB) (Arabic: مطار دبي الدولي‎ ‎ ) is the primary international airport serving Dubai, United Arab Emirates and is the world's busiest airport by international passenger traffic.  It is also the 3rd busiest airport in the world by passenger traffic, the 6th busiest cargo airport in world, the busiest airport for Airbus A380 and Boeing 777 movements, and the busiest airport in the world operating with only two runways.  In 2016, DXB handled 83.6 million passengers, 2.59 million tonnes of cargo and registered 418,220 aircraft movements. The Maryland Transit Administration (MTA) is a state-operated mass transit administration in Maryland, and is part of the Maryland Department of Transportation.  It is better known as MTA Maryland to avoid confusion with other cities' transit agencies who share the initials MTA.  The MTA operates a comprehensive transit system throughout the Baltimore-Washington Metropolitan Area.  There are 80 bus lines serving Baltimore's public transportation needs, along with other services that include the Light Rail, Metro Subway, and MARC Train.  With nearly half the population of Baltimore residents lacking access to a car, the MTA is an important part of the regional transit picture.  The system has many connections to other transit agencies of Central Maryland, Washington, D.C., Northern Virginia, and south-central Pennsylvania (Hanover, Harrisburg, and York): WMATA, Charm City Circulator, Regional Transportation Agency of Central Maryland, Annapolis Transit, Rabbit Transit, Ride-On, and TransIT. The Baltimore–Washington metropolitan area is a combined statistical area consisting of the overlapping labor market region of the cities of Washington, D.C. and Baltimore, Maryland.  The region includes Central Maryland, Northern Virginia, three counties in the Eastern Panhandle of West Virginia, and one county in South Central Pennsylvania.  It is the most educated, highest-income, and fourth largest combined statistical area in the United States. This is a list of busiest airports in Asia, ranked by total passengers per year, which includes arrival, departure and transit passengers.  Beijing Capital International Airport has been the busiest airport in Asia since 2009.  The tables also shows the percentage change in total passenger traffic over last year.  Asian airports are those that are located in the 48 countries and 6 dependent states as defined by UN and fall within the Asian region.  Airports in Moscow and Istanbul airport are located in the European part of their respective countries and so are not included in this list.  While Turkey is a member state of The Council of Europe which includes Turkish airspace within Europe and hence traffic of Turkish airports, even those falling in the Asian region, are included in the busiest airport in Europe list. The Central Maryland Transportation Alliance (CMTA) is a coalition of Baltimore area business, civic and nonprofit groups intent on improving travel within Central Maryland, which consists of Baltimore City and the surrounding jurisdictions of Anne Arundel County, Baltimore County, Carroll County, Harford County and Howard County.  The group’s stated objectives are to reduce congestion, limit sprawl, increase job opportunities and make it easier, faster and more efficient for anyone to travel within Central Maryland. Baltimore/Washington International Thurgood Marshall Airport (IATA: BWI, ICAO: KBWI, FAA LID: BWI) is an international airport located in Linthicum in northern unincorporated Anne Arundel County, Maryland.  The airport is 9 miles south of downtown Baltimore and 32 miles northeast of Washington, D.C. It is the busiest, by passenger count, of three major airports serving the Baltimore–Washington metropolitan area in the United States, the other two being Ronald Reagan Washington National Airport and Washington Dulles International Airport.  It is commonly referred to as BWI or BWI Marshall.  The airport is named after Thurgood Marshall, a Baltimore native who became the first African American to serve on the Supreme Court of the United States. Heathrow Airport (also known as London Heathrow) (IATA: LHR, ICAO: EGLL) is a major international airport in London, United Kingdom.  Heathrow is the second busiest airport in the world by international passenger traffic (surpassed by Dubai International in 2014), as well as the busiest airport in Europe by passenger traffic, and the seventh busiest airport in the world by total passenger traffic.  In 2016, it handled a record 75.7 million passengers, a 1.0% increase from 2015. WDCH-FM (99.1 FM; "Bloomberg 99.1 and 105.7 HD2") is a radio station currently broadcasting a business news format.  Licensed to the eastern suburb of Bowie, Maryland, in Prince George's County, it serves the central Maryland and northern Virginia metropolitan areas of Baltimore, Maryland/Washington, D.C. region.  The station is currently owned by CBS Radio and operated by Bloomberg L.P. Its transmitter is located near Crofton, Maryland in suburban central Anne Arundel County to the east, and the broadcasting studios are located near the Washington Navy Yard along the north/west bank of the Anacostia River (Eastern Branch of the Potomac River) in Southeast Washington.  WDCH-FM often airs D.C. United soccer and Washington Wizards pro basketball games in the NBA due to sister station WJFK-FM, 106.7 "The Fan" usually already covering a game elsewhere. Grantley Adams International Airport (GAIA) (IATA: BGI, ICAO: TBPB) is the international airport of Barbados, located in Seawell, Christ Church.  It is the only designated port of entry for persons arriving and departing by air in Barbados and operates as a major gateway to the Eastern Caribbean.  The airport has direct service to destinations in the United States, Canada, Central America and Europe and serves as the second hub for LIAT.  In 2016, the airport was the 8th busiest airport in the Caribbean region; and the third busiest airport in the Lesser Antilles; after Queen Beatrix International Airport located in Aruba, and Pointe-à-Pitre International Airport located in the Republic of France within the island of Guadeloupe.  GAIA, also remains an important air-link for cruise ship passengers departing and arriving at the Port of Bridgetown, and a base of operations for the Regional Security System (RSS), and the Regional (Caribbean) Police Training Centre.
Answer: Baltimore/Washington International