Why didn't the Delhi govt vacate the Nizamuddin Markaz in time?

Nearly 35 percent of the Coronavirus positive cases have resulted due to Tablighi Jamaat event that took place in Delhi's Nizamuddin Markaz. Now, the police officials are tracking down the people associated with the Jamaat. They are then quarantined as well. The only question here is that why didn't the Delhi government vacate the Nizamuddin Markaz in time? Why did the government keep sending notices only?