There are several romanisation schemes for the Malayalam script, including ITRANS and ISO 15919.
The lack of diacritics on keyboards led to the adoption of ASCII only romanisation schemes.
ASCII only schemes remain popular in email correspondence and input methods because of their ease of entry.
The disadvantage of ASCII schemes is that letter case is meaningful, so that transliterated names may not be capitalised.
ISO 15919 "Transliteration of Devanagari and related Indic scripts into Latin characters" is one of a series of international standards for romanisation.