Mirza,
You had several bugs/typos:
- Y and y are different variables -- be careful of capitalization
- you need a list of equations -- not a list of lists
- you use NeumannValue incorrectly -- it is not used in the boundary conditions it is in the equation itself (even though it acts at the boundary)
- you use extra lists in places they do not belong (i.e inside of DirichletCondition, the integration variable, etc.)
this computes a solution:
eq1 = {D[Subscript[\[Theta], c][x, y], x] -
2/(y - y^2)*D[Subscript[\[Theta], c][x, y], y, y] ==
NeumannValue[0, y == 1]};
ic = {Subscript[\[Theta], c][0, y] == 1};
bc = {DirichletCondition[Subscript[\[Theta], c][x, y] == 0, y == 0]};
sol = NDSolve[Join[eq1, ic, bc],
Subscript[\[Theta], c], {x, 0, 1}, {y, 0, 1}]
Regards,
Neil