Dear Mahadev,
" TRAINEE " will certainly be an ambiguous term when persons are employed at any posts in an industrial organization where no scheme of apprenticeship or training is available as per the provisions of any law or its own standing orders. I think that you have taken the cue for the stipend mentioned in your post from the Central Govt Notification in GSR 680(E) dated 22-09-2014 fixing the minimum rate of stipend for the trade apprentices.
Already, a trainee is entitled to bonus,gratuity, employees compensation in case of employment accidents if he satisfies the eligibility conditions prescribed under the respective enactments as per various case laws. Similarly, if the trainees are not under any apprenticeship scheme, they would be "employees" for the purpose of EPF Act,1952. In addition, your statement " trainees ( not under Apprenticeship Act ) engaged for a duration of 4 to 6 weeks in a garment industry " confirms the fact of the absence of any scheme of institutional apprenticeship or training as well as gives rise to the suspicion whether the designation is a camouflage for the temporary employees employed in peak seasons only. Even If it is a kind of " on the job training " following the incumbents' regular appointments, paying at a particular rate for the period less than the minimum rates, if any fixed under the Minimum Wages Act,1948 will be an offence.
Therefore, there can not be any positive comment on your proposal unless you disclose all the relevant details.