Hello dear,
When the appropriate government fixes or revises the minimum wage for different categories of employees (i.e., unskilled, semiskilled, skilled, etc.), then one of the clauses in that notification is about linking this wage with the Consumer Price Index (CPI), which is declared every six months based on the data provided by the Statistical Department of State/Center governments. Based on the CPI, the appropriate government then enhances the wage of each category. This enhancement is merged with the earlier fixed or revised minimum wage. By such merger, a new minimum wage is formed and is treated as the minimum wage fixed by the government.
Hence, if you split the minimum wage into Basic + DA, it will not save you any money as all benefits under the Labour Laws are given to workmen on Basic + DA. My experience is that employers want to split the minimum wage so that they can save some money on contributions to ESI, PF, bonus, gratuity, etc.
Under the Minimum Wages Act, there is no percentage fixed for splitting it into Basic and DA. Please decide for yourself, keeping in view that it is a welfare legislation and even ethics demand that the legal share of poor workmen or, for that matter, the share of anyone, should not be taken away.
Best wishes and regards.