Policy regarding Deduction of Salary/Wages for Declared Holidays

Dear Professional Colleagues,
We have a Policy where if any employee works less than 20 days in any particular month, he/she will loose the benefit of declared holidays i.e., all Sundays and Paid Holidays under National and Festival Holidays Act will not be considered for salary computation and they loose Salary/Wages all Sundays and holidays for that particular month.
Now my question is What is the Legal Sanctity for enforcing such Policy and whether such Policy is legally compliant or is it violation of law.
Secondly, Whether we can give proportionate holidays against physical working in a month for monthly rated employees on the rolls of the Company. For Example if some body has worked for 17 days in a month they get only three Sundays in that month.
I request your validated views on this and how far such policies are supported in the eye of Industrial Law and rules.

Dear friend,
It would have been better had you mentioned the type or classification of your establishment. However, let me proceed to answer your queries based on the assumption that it is an " industrial establishment " as defined u/s 2(4) of the Karnataka Industrial Establishments ( National & Festival Holidays )Act,1963; even otherwise, the basic principles underlying the grant of National and Festival holidays and the weekly holiday in respect of employees employed in industrial establishments situated elsewhere are one and the same.
Section 3(1) of the KNIE(N&FH)Act,1963 mandates that the employees of every industrial establishment shall be allowed 3 national holidays on January,26, August,15 and October,2 and 5 other festival holidays in every calendar year. In addition, sec.3A provides for paid holidays on the polling day for the House of People or to the State Legislative Assembly notified under the People's Representation Act.
Sec.5(1) of the Act states that the above holidays are paid holidays.
However, the grant of such holidays with wages are controlled with reference to certain minimum number of service in the establishment by the proviso to Sec.5(2) of the Act only in respect of the 5 festival holidays. In other words, to avail of a paid holiday on the occasion of any approved festival, an employee should have been in the service of the employer for a total period of 30 days within a continuous period of 90 days which includes a weekly holiday or any other holiday or any authorised leave.
Regarding your query on grant of weekly holiday, every 7th day following 6 working days should be a holiday is the general principle. It may vary according to the nature of the activity of the establishment. But the term "working day" would include days spent on authorised leave by the employee apart from the actual days he worked. Therefore, if you take only the physical working days actually worked by the employee in a month for the purpose of his holidays, I am afraid, your act is more in violation than compliance.
No policy of an establishment can run counter to the provisions of any law.
Hence, I would request you to review your policy by juxtaposing its principles with the provisions of the Labour Laws applicable to your establishment in this regard.