'Unable to process source' error

I am installing ros in Ubuntu 16.04 and all went well until the following command

rosdep update

The error I am getting is as follows

reading in sources list data from /etc/ros/rosdep/sources.list.d

ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]: (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)

ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml]: (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml)

ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml]: (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml)

ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml]: (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml)

ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml]: Failed to download target platform data for gbpdistro:

error [Errno -3] Temporary failure in name resolution> Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index.yaml

ERROR: error loading sources list: (https://raw.githubusercontent.com/ros/rosdistro/master/index.yaml)>

I am installing using this. Issue is happening at command 2 of 1.5;

I edited the /etc/environment file with export statements and no issue with such proxy statements.

Is there any need to place the export proxy statements any where?

How to fix this issue and update properly?