What was the main reason behind Mahatma Gandhi's decision to take up the Khilafat issue?

Why did Mahatma Gandhi support the Khilafat Movement?

The first mass movement started by Mahatma Gandhi was

After which incident the Non-Cooperation movement was withdrawn by Mahatma Gandhi?

The Khilafat movement was started by

The title given by the British Government to Mahatma Gandhi which he surrendered during the Non-Cooperation Movement was: