| cleaner fuel | 4.61 | ...industrial research into cleaner fuels. | ||
| cleaner air | 4.28 | Cleaner air. | ||
| cleaner gasoline | 1.84 | Oil refiners will have to make cleaner gasoline, too. | ||
| cleaner car | 1.78 | Was it a cleaner car engine? | ||
| cleaner environment | 1.58 | That would mean a cleaner environment. | ||
| cleaner technology | 0.99 | Cleaner technologies are not being introduced. | ||
| cleaner water | 0.86 | Urban areas would get cleaner water, but less of it. | ||
| cleaner vehicle | 0.79 | It virtually creates its own market for cleaner vehicles and fuels. | ||
| cleaner window | 0.72 | Confessions of a window cleaner. | ||
| cleaner energy | 0.66 | Instead, a cleaner energy source had to be discovered, he decided. | ||
| cleaner engine | 0.59 | In response, automakers have been working on cleaner engines and cleaner fuels. | ||
| cleaner politics | 0.59 | It begins to look like a GOP war on cleaner politics. | ||
| cleaner gas | 0.53 | To meet emission demands, many automakers are developing cleaner gas and diesel engines. | ||
| cleaner source | 0.53 | Ramos said the pipelines would dramatically increase the use in Southeast Asia of natural gas, a cleaner source of power. | ||
| cleaner burn | 0.39 | Petrol and diesel burn cleaner with this method. | ||
| cleaner diesel | 0.39 | Incentives to refiners that produce cleaner diesel fuel would boost production. | ||
| cleaner election | 0.39 | Zedillo has earned respect for personal integrity and his commitment to cleaner elections. | ||
| cleaner government | 0.39 | He has also promised to seek a gentler, welfare-oriented society and cleaner government. | ||
| cleaner alternative | 0.33 | Demand for natural gas is growing in China as the country searches for a cleaner alternative to coal, its main energy source. | ||
| cleaner bus | 0.33 | Financial help for cleaner UK buses? |