Apart from Basic Salary, Dearness Allowances (variable according to changes in the cost of living index or fixed as a percentage of basic pay) and Retaining allowances (allowances paid to employees to retain their skills, especially when there is no work due to any reason), are part of the salary for the purpose of EPF contribution. If the salary structure does not include any DA but includes something called 'special allowance', the same may also be treated as part of the salary for the purpose of EPF contribution. The reason being that special allowances may be interpreted as an allowance to meet changes in the cost of living and as such, it will have all the attributes of DA.
Regards,
Madhu.T.K