Do you have PostgreSQL installed ? if yes, check the pg_config location in :

• For linux : /usr/pgsql-/bin/pg_config
• For windows : C:\Program Files\PostgreSQL<version>\bin\pg_config.exe

Then, update the PATH :

• For linux : export PATH=$PATH:/path/to/pg_config/executable

Otherwise, you can try :

sudo apt install libpq-dev python3-dev
sudo apt install build-essential