In 1893, the Indian freedom fighter Lokmanya Tilak praised the celebration of sarvajanik Ganesha utsav in his newspaper, Kesari, and dedicated his efforts to launch the annual domestic festival into a large, well-organised public event.
Tilak recognized Ganesha’s appeal as “the god for everybody”,he chose Ganesha as the god that bridged “the gap between Brahmins and non-Brahmins”, thereby building a grassroots unity across them to oppose British colonial rule.

The British Empire, after 1870 out of fear of seditious assemblies, had passed a series of ordinances that banned public assembly for social and political purposes of more than 20 people in British India, but exempted religious  assembly for Friday mosque prayers under pressure from the Indian Muslim community. Tilak believed that this effectively blocked the public assembly of Hindus whose religion did not mandate daily prayers or weekly gatherings, and he leveraged this religious exemption to make Ganesh Chaturthi to circumvent the British colonial law on large public assembly. He was the first to install large public images of Ganesha in pavilions in Bombay Presidency, and other celebratory events at the festival.

Tilak recruited and passionately committed himself to god Ganesha after the 1893 Hindu-Muslim communal violence in Bombay and the Deccan riots, when he felt  that the British India government under Lord Harris had repeatedly taken sides and not treated Hindus fairly because Hindus were not well organized.In Tilak’s estimate, Ganesha worship and processions were already popular in rural and urban Hindu populations, across social castes and classes in Baroda,Gwalior, Pune and most of the Maratha region in the 18th century.In 1893, Tilak helped expand Ganesh Chaturthi festival into a mass community event and a hidden means for political activism, intellectual discourse, poetry recitals, plays, concerts, and folk dances.

Reference : https://en.wikipedia.org/wiki/Ganesh_Chaturthi