Over 1,800 teachers from more than 1,100 secondary schools will participate in the stir. The strike call has been given by the Greater Bombay Secondary School Teachers' Association and the Suburban Secondary Teachers' Association.

A dharna will also be held at Azad Maidan on Friday, after which the teachers' charter of demands will be handed over to the district collector.

``Though it's a one-day strike, it will upset the exam schedule, since first-term exams in many schools begin on Friday. In view of the strike, we have also decided to advance the practicals in our school by a day,'' said Father Herman Castelino, principal of St Xavier's High School, Fort.

President of the Suburban Secondary Teachers' Association, S Lugade, said: ``Nearly 5 lakh teachers across the state are observing the strike. Our main demand is implementation of theFifth Pay Commission, which offers better salary scales compared with the state-appointed Sukhthankar committee.'' The Maharashtra Secondary Teachers' Federation had recently condemned the Sukhthankar committee report for stopping teachers' increments on flimsy grounds.

The teachers have also demanded their back wages be paid in cash, instead of being deposited in the provident fund, as has been the case in the past. Like Central government employees, teachers want all allowances, facilities and advances to be given to them with effect from August 1, 1997.

The teachers' representatives also said if their demands weren't accepted on Friday, they may have to resort to an indefinite strike.

While deputy director of education D C Deshmukh said he was unaware of the stir, many institute heads have already resigned to the idea of no work on Friday. ``Our teachers have no option but to join the strike. But I do feel the state should not thwart implementation of the Fifth Pay Commission as it attempts toupgrade the low financial and social status of the teaching community,'' said director of St John's High School (Goregaon), Dilip Mirchandani.

The headmaster of the same school, PKG Nair, said: ``The Fifth Pay Commission has given primary teachers a basic salary between Rs 4,500 and Rs 7,000. But the Sukhthankar committee has recommended a basic salary in the range of Rs 4,000 and Rs 6,000. Similarly, salaries of secondary teachers and head-masters have been reduced by the committee.''

Principal of Patuck Technical High School & Junior College, KGK Kurup, said: ``Two arguments of the Sukhthankar committee will prove suicidal for the teaching community. One, that teachers in Maharashtra outnumber teachers under the Central government. Two, that teachers' pay scales are very high and resented by school administrations. But will this apply to UGC teachers? Surely not!''