I'm Indian and for me saag is "leafy greens" too. Spinach to be more particular.
The thing is that in India some meanings change with geography and location. For example, for me bhujia meant this [1] for the longest time. However, when I moved to a different part of the country, bhujia also meant potato fritters. Then, there is bhaji which means fried veggies. But some people also call potato fritters as bhaji.