* You can ignore SSL errors by setting pypi.org and files.pythonhosted.org as trusted hosts.
```
pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org <package_name>
```
Note: Sometime during April 2018, the Python Package Index was migrated from pypi.python.org to pypi.org. This means "trusted-host" commands using the old domain no longer work.

* Permanent Fix:
You may want to add the trusted hosts and proxy to your config file.
```
pip.ini (Windows) or pip.conf (unix)

[global]
trusted-host = pypi.python.org
               pypi.org
               files.pythonhosted.org
```