how reliable is your evidence ? I have seen tea plantations in the Azores and I'm pretty sure that was not a landslide area
are you taking certain areas in India as typical for all tea-growing areas ?
and if so, how can you be sure that it's not some other factor such as drainage or south-facing orientation rather than being a land slide area
or maybe growing tea in a hilly area makes them more likely to become land slide zones if you drench them with monsoon rains
in short, how can you be sure you're not overgeneralising from a limited data set ?
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