trans-2-Methylcyclohexanol is treated with $\mathrm{POCl}{}_3$ in pyridine, which converts $\mathrm{OH}$ to a good leaving group and causes E2 anti elimination without carbocation. The major alkene is:

In the trans isomer the stable diequatorial chair cannot eliminate. The diaxial conformer has the leaving group axial and the C2 methyl axial, so the C2-H is equatorial; only the axial H on C6 is anti. Elimination thus gives the C1=C6 alkene, 3-methylcyclohexene. Conc. $\mathrm{H}{}_2\mathrm{SO}{}_4$ (E1) would instead give 1-methylcyclohexene.