Question

how did the non cooperation movement spread in cities across the country 

Answer 1

I'll answer in simple words, you can add effects to it:
a) People began boycotting foriegn cloth and prefered khadi.
b)They disowned titles.
c) They left government institutions, students stopped going to school and lawyers left courts.
But khadi was very expensive and there were no other indian institutions to replace the boycotted ones, so the movement stopped. I have no idea about the economic front sorry.

Answer 2

Various people saw the non cooperation movement in different ways:-
In the cities students , teachers, lawyer s left government institutions. Foreign cloth was boycotted liquor shops picketed

Inthe countryside
The peasants were led by a man named baba ramchandran who was an indentured labourer . They revolted against the zamindars and landlords and demand low revenue and abolish serfdom . This happened in the village of awadh . Later jawaharlal nehru went from village to village organising the peasants and formed the oudh kissan sabha

In the gudem hills of andhra pradesh the tribals led a guerilla movement. They demand entry into reserved foreats etc they were led by Alluri sitaram raju . He told them about mahatma Gandhi and the non cooperation movement. Thousands of tribals broke the forest laws and entered into the forest and grazed there cattle