how did the old city of delhi change under british rule please give me answer in short

Many changes took place during the British to the nature and character of Delhi since it became the capital in 1911. Some of the important changes are:

1. Unlike other cities like Calcutta and Madras, initially, the British lived alongside the wealthy residents of Delhi in the walled city. This helped in many British adopting Urdu and Persian as a language and appreciating the beauty of the Indian languages.
2. The Delhi College was established in 1792 which was a centre for studies in humanities, languages and science.
3. In order to erase the Mughal memory and impact on the minds of Indians, many clearing activities were undertaken. Gardens, pavilions and mosques around the fort were destroyed. Some mosques like Zinat-al-Masjid was converted into a bakery. Prayer was not allowed at Jamma Masjid for over 5 years. Canals were filled up and thus, the beauty of the old city of Delhi was destroyed.
4. The walls on the west of Shahjahanabad were broken and railway was laid in the1870s. 
5. The British began to reside in the Civil Lines away from the Hindus and Muslims.
6. After shifting the capital to Delhi in 1911, a new city New Delhi was planned and constructed on and around the Raisina Hill. Edward Lutyens and Herbert Baker planned and laid out the new city, its buildings like the present day Rashtrapati Bhawan, Parliament House and the Secreteriat buildings. Avenues like the Rajpath were laid out. New Delhi had better water supply, drainage and sewage disposal making it hygenic and clean in contrast with the Old City. New Delhi took 20 years to be built.