Would you check my writing please?

Hi.

Hi dear Jenny.

I'm leaving India for the U.S. tomorrow night. Before that, I'd like to climb a great hill near the hotel. There is a huge castle on top of it.This hill is famous for its fresh and of course foggy air. I really prefer foggy air to that of the downtown where people smoke all of the time. You should give up smoking too since it can damage your health. Most of the smokers know about it but they still smoke. Generally, smokers don't believe that their action can be dangerous enough to kill them soon or late.

Now I have to buy some canned food and groceries for my short trip to the hill. A lot of people join together in early mornings to climb it. It seems to be so fun. The weather is very nice too. There are some clouds in the sky that pass over the sun occasionally. Even better, the top of the hill is covered with snow so I can have a snowball fight with some friends.
To be honest, I can't express my feelings in words. I want to become a habitual mountain climber when I come back to the U.S. I bought a professional backpack for this purpose; it's really cozy.

Kiss your sisters for me, especially Maria.

See you soon.

Sara.