Explanation: In the context of international travel, particularly for long distances such as from Delhi to Washington, the choice of transport mode is crucial. The primary modes of transport include airways, railways, waterways, and roadways. Each mode has its own advantages and limitations, which must be considered based on the specific travel requirements.
**Airways** are the most suitable mode for long-distance international travel. Air travel is characterized by its speed, efficiency, and ability to cover vast distances in a short amount of time. Airports are strategically located in major cities around the world, making air travel a convenient option for international travelers. For a journey from Delhi to Washington, airways are the only practical mode of transport, as they can efficiently cross the vast distance and the Atlantic Ocean.
**Railways**, on the other hand, are limited to land and are not suitable for crossing oceans. While railways are efficient for land-based travel within continents, they are not practical for long-distance international travel that involves crossing oceans. The distance between Delhi and Washington is too vast and involves crossing the Atlantic Ocean, making railways an impractical choice for this route.
**Waterways** can be used for international travel, but they are not efficient for long-distance travel due to the time required. Additionally, waterways are not directly connected between Delhi and Washington, making this mode of transport impractical for this specific journey. While waterways are useful for shorter distances and for transporting goods, they are not suitable for the long-distance travel required to go from Delhi to Washington.
**Roadways** are also limited to land and cannot cross oceans. The distance between Delhi and Washington is too vast and involves crossing the Atlantic Ocean, making roadways impractical for this route. Additionally, the journey would be extremely time-consuming and logistically challenging, making it an impractical choice for international travel.
In summary, for traveling from Delhi to Washington, airways are the most suitable mode of transport due to their speed, efficiency, and ability to cover vast distances, including crossing oceans. Airways provide the most practical and convenient option for long-distance international travel.