Hi, Please go through the contents of the above link:
https://www.keka.com/library/minimum-wages/tamilnadu.
HRA and the Tamil Nadu Shops & Establishments Act
As far as I know, there is no strict rule prescribing any percentage of HRA as part of the salary under the TN Shops & Establishments Act. Even under the Minimum Wages notified by the TN Government, there is no such stipulation for HRA. However, there is the Basic and DA part of the minimum wages, with no HRA stipulated.
Impact of Reducing HRA
However, any attempt affecting the present emoluments will be a contentious issue, and HRA is one such matter. An attempt to reduce the percentage thereof will not be acceptable to the employees. Perhaps there should be an agreement or Letter of Appointment where these rates could have been mentioned. If so, it's not possible to effect a unilateral action by the employer without the formal approval of all employees concerned.