If the air temperature at sea level is 20 degrees Celsius, the temperature at 3000 meters will be approximately 7 degrees C.
They are electromagnetic waves because mechanical waves have to be physically created by something, while electromagnetic waves are just emitted without any effort or force.
India and Pakistan used to be one country up until 1947 - when the Partition of India happened.
Ever since then their relationship has been very problematic - Kashmir is disputed between the two nations, and their relationship can be described as competition (for example they both have nuclear arms and had a kind of unofficial competition over who has more ).