Local resistance groups in upland areas, where thousands are settled for generations farming small pieces of lands, have extended support to the protest.
The opposition LDF has rejected plea of Chief Minister Oommen Chandy to desist from the shut-down protest since the Centre had clarified that it had only issued a draft notification and a final call on the report is yet to be made.
Early reports from different centres said buses, taxis and autorickshaws kept off the roads and shops remained closed.
The state-run KSRTC, however, operated its services to Pampa for Sabarimala pilgrims from here and other centres.
According to police, no violence has been reported in the initial hours of the protest, which got underway at 6 am.
In Idukki, the High Range Samrakshna Samiti, which has support from various political parties and the Catholic church, began a 48-hour block last midnight.
Pastoral letters had been read out in churches in Idukki and Thamarassery, expressing deep anxiety that implementation of the report might lead to large-scale eviction of farmers.
As per the draft notification issued by the Ministry of Forest and Environment, ecologically damaging activities like mining, quarrying and building of thermal power plants and big building complexes would be banned to protect the Western Ghats ranges, running through six states, from further ecological devastation.
However, two months' time has been given for the public or groups to air their views and grievances before issuing the final notification.
Except BJP, most mainstream political parties, including Congress and its partners in the UDF have voiced concern over implications of the implementation of the report in the state.
Photograph: Reuters
Relief for CPI-M: Vijayan no longer an accused in SNC-Lavalin case
IMAGES: Chugging through the wild beauty of the Western Ghats
Fire and smoke at Chandy's programme venue creates tension
Do ordinary Indians know their national leaders?
Attack on Chandy: CPI-M workers held, blame game on