How did the Old City of Delhi change under British rule?

The British wanted Delhi to forget its Mughal past so it changed the old city of Delhi. 

The area around the Fort was completely cleared of gardens, pavilions and mosques (though temples were left intact). The British wanted a clear ground for security reasons. Mosques in particular were either destroyed, or put to other uses. For instance, the Zinatal-Masjid was converted into a bakery. No worship was allowed in the Jama Masjid for five years. One-third of the city was demolished, and its canals were filled up.

In the 1870s, the western walls of Shahjahanabad were broken to establish the railway and to allow the city to expand beyond the walls. The British now began living in the sprawling Civil Lines area that came up in the north, away from the Indians in the Walled City. The Delhi College was turned into a school, and shut down in 1877.