Related by context. Frequent words. (Click for all words.) 65 exhaust emission 56 emission 55 stricter 55 greenhouse gas emission 54 exhaust emissions 54 GHG emission 54 carbon dioxide emission 53 tailpipe emissions 52 emissions 52 stringent 51 pollutant emissions 51 smog forming emissions 50 fleetwide average 49 Stricter 49 CO2 emission 49 regulations 49 greenhouse gas emissions 48 Emission 48 greenhouse gas 48 Board CARB 48 pollution 47 CAFE standards 47 greenhouse emissions 47 pickups SUVs 47 carbon dioxide emissions 47 rigorously enforced 47 Bharat Stage 46 emission reduction 46 carbon emission 46 Emissions 46 RoHS directive 46 emission norms 46 air pollution 45 ozone depleting chemicals 45 CO2 emissions 45 mandating 45 strict 45 impose stricter 45 Stringent 45 SUVs pickups 45 greenhouse gases 44 particulate emissions 44 gas recirculation 44 speed limiters 44 CARB 44 homologation 44 imposing stricter 44 Pavley 44 GHG 43 technologically feasible 43 C# emissions 43 greenhouse gasses 43 carbon emissions 43 global warming gases 43 GHG emissions 43 reduce carbon emissions 43 GHG reduction 43 tighter 43 mandates 43 greenhouse gas emission reductions 43 cleaner fuels 43 reducing CO2 emissions 43 VOC emissions 43 Average Fuel 43 legislated 43 environmental 43 smog 43 Automakers 43 RoHS Directive 43 toughening 42 NOx emissions 42 regulatory 42 strictly enforced 42 standards 42 nitrogen oxide emissions 42 Tougher 42 GHGs 42 diesel particulate filter 42 polluter pays 42 mercury emissions 42 nitrogen oxide NOx 42 particulate filter 42 federally mandated 42 emission reductions 42 zero emission 42 Hazardous Substances 42 enacted 42 regs 42 carbon emission reductions 42 particulate matter emissions 42 carmakers 42 NOx 41 sulfur fuels 41 automobiles 41 compliances 41 diesel powered 41 PZEV 41 biodiesel blends 41 WEEE Directive 41 leaded gasoline 41 heat trapping emissions