In your first post you mentioned this: How do you set current directory (full path) in an environment variable?
The current working directory is always seen from where one starts the script (not where the script itself resides).
If your script resides in /home/<user>/downloads/application/ and you run it from /home/prashant, the pwd command will print /home/prashant and if you run it from /tmp it will print /tmp.
I'm not sure if the /home/<user> part needs to be dynamic in your case (unsure as in: are you asking the correct question). If so you can add the extra part (downloads/application) as mentioned in post #6.
If it does not need to be dynamic, but is always /home/prashant/downloads/application you can declare that in one go (export MYHOME=/home/prashant/downloads/application).
$ ls -l /data/Downloads/run.sh
-rwxr-x--- 1 druuna internet 97 Jul 10 12:37 /data/Downloads/run.sh
$ cat /data/Downloads/run.sh
$ cd /tmp/
The bold part adds a directory (lib in the first example) to the output og pwd. You now have 2 exported variables:
MYHOME -> holds the current working directory, which is dynamic and depends on where the script is started (/home/druuna in the first example)
PYTHONHOME -> holds the content of MYHOME + the added directory, you end up with: /home/druuna/lib
Hope this clears things up.